Ambiguously Jewish: One of his parents was Jewish and he knows a bit of Yiddish and some Jewish prayer. Other than that, he doesn't display any Jewish mannerisms and Anthony Edwards himself is not Jewish.
Back for the Finale: While he doesn't appear in the final episode, a flashback episode midway through the last season showing Catherine Banfield's first encounter with County Hospital reveals that Greene treated her son (sadly, the son was already terminally ill). The event clearly takes place shortly before his death, which adds a further bit of melancholy.
Beta Couple: Mark and Elizabeth's relationship has aspects of this—they don't get together until after Doug leaves and the writers clearly needed a couple to replace Doug and Carol. While it is at the forefront (mainly because Mark was the de facto main character), their relationship is relatively problem free and problems only really arise when Elizabeth gives birth and Rachel comes to live with them.
Betty and Veronica: For Mark it seems to be Susan and Jen and eventually Susan and Elizabeth.
Bittersweet Ending: Despite dying of cancer, in the very least he got to spend his last moments with his family and in an island paradise.
Book Ends: When his father died Mark spent his last days repairing their relationship. When he was dying he pulled Rachel out of school so that he could spend his last moments with her and try to repair their relationship.
The Casanova/ Casanova Wannabe: Amazingly, despite never having slept with anyone other than his wife, Mark manages to pick it up after his divorce and Susan's leaving. Unfortunately he's not so good at the finer aspects of being a player, scheduling three dates on the same night that all the participants find out about (Nina, the psych attending, eventually agrees to go out with him).
Chronic Backstabbing Disorder: His position of authority puts him in difficult standing with his friends, and often times had to make tough choices involving them. He rarely, if ever, outright stabbed anyone in the back, unlike Kerry.
Deadpan Snarker: Develops quite a sense of humour when he was diagnosed with a brain tumour.
Heroic BSOD: He suffers these repeatedly—after mishandling a childbirth, resulting in the mother's death, after his wife leaves him for another man, after Susan leaves him before they can even have a relationship, after being beaten up (losing Susan made him feel bad, being beaten up made him feel worse), a small one after his father dies and after learning that his brain tumor has returned and is now inoperable.
I Want My Beloved to Be Happy: In a deleted scene for On The Beach, Mark tells Elizabeth he has absolutely no problem with the idea of her getting re-married again, saying that she deserves to be happy and that Ella deserves a father. Elizabeth is very resistant to the idea and tells Mark he should stop talking this way.
I Was Quite a Looker: The, now balding, Mark tells Rachel that he used to have hair down to his shoulders. Anyone who's seen Anthony Edwards in Fast Times can vouch for this.
Magnetic Hero: Is very respected by his colleagues. Even lone wolf Benton sometimes goes to Mark for advice. Works posthumously too, Banfield agrees to give Carter work in the ER whilst he's in Chicago because she learned that Mark was one of his teachers (Mark treated her son).
Opposites Attract: Mark and Elizabeth show shades of this. While they get along very well their personalities are quite different. Mark is rather soft and more patient, more willing to understand people and to give them second chances. Elizabeth is a lot tougher and a lot harsher. Their respective personality differences become apparent when Ella overdoses on Rachel's ecstasy, Elizabeth wants Mark to call the police and wants Rachel out of the house (and tells her as much), whereas Mark (probably because Rachel is his daughter) just wants to work things out and to try and help his daughter. Elizabeth is also more career-oriented, taking up Romano's offer of the Associate Chief of Surgery position despite suspecting ulterior motives, whereas Mark is content just to run the ER.
Parental Neglect: Claims that, as a teenager, he started acting out in frustration because his father was never around. Mark starts to fear, even before his tumour recurs, that Rachel's acting out is because he made the same mistakes.
Parental Substitute: For Carter. Mark gives Carter the nurturing encouragement that he doesn't get from Benton, and they fill a need in each other's lives, as Mark doesn't get to see his daughter very often and Carter's parents are often on vacation somewhere.
Posthumous Character: On The Beach is somewhat non-linear, in that it aired after The Letter, in which the ER staff are notified that he has died, and yet it takes place immediately after Orion In The Sky (Mark's last day), during Brothers and Sisters (Elizabeth goes to Hawaii to be with Mark) and between The Letter (Mark's death obviously happened before the episode, but Mark's funeral happened afterwards). The final season episode that featured his "return" was actually a flashback to his last days at the hospital.
Took a Level in Jerkass: After Mark gets beaten up he becomes cynical and unpleasant and while arguably he deals with some patients the way they should be dealt with,most of the time he just comes off as a total jerk. It doesn't last.
After his first tumour, Mark begins to suffer personality changes. While not as bad as when he got beaten up, Susan reprimands him at one point for being so harsh with patients and tells him that he isn't quite the kind and caring Mark Greene she used to know.
A deleted scene from Orion In The Sky (Mark's last day at County) has Mark and Susan talking about what happened at Union Station five years later. Susan obliquely asks Mark if she hadn't moved away, they'd be together. Mark then mentions his grandfather and how he used to say that everything happens for a reason, then he says it was just one of those things that sounded even stupider as he got older.
Vigilante Execution: He not only refused to help the man who threatened to kill him and his family, he taunted him as he died by holding up the shock paddles in front him. He never suffered any legal ramifications for doing so.
Yank the Dog's Chain: Anspaugh, at one point, promises to offer Mark a tenured position at the hospital within three years if he agrees to stay on staff and not join a NASA program. This means that Mark could get tenure as early as 2002. Mark died in 2002.
Chuck Cunningham Syndrome: In the first season, it's mentioned at least twice that he has a son. Scant details are given about this except the child's age—8—and that he doesn't even know the boy's name. This is never mentioned again throughout the rest of his time on the show, not even during key storylines where it would make sense—his abusive father resurfacing and later dying, his and Carol's decision to have a baby. At one point, when a character asks if he has any kids, he says "no".
Doug himself doesn't appear at Mark's funeral—without any explanation as to why—even though they were best friends. He and Carol also didn't appear at his wedding to Elizabeth, although that can be explained away (a storm essentially grounded all of Mark and Elizabeth's out-of-state guests, including Rachel).
Heel Realization/Heroic BSOD: After one of his random one-night-stands dies of an overdose and it really begins to sink in just how much he's screwed up his life.
Heterosexual Life-Partners: Mark and Doug are best friends, and seem to spend a lot of time together. As Doug is such a 'cowboy' (as some of the other doctors put it) Mark's position of authority often complicates their friendship. However Mark, more often than not, is perfectly willing to advocate for Doug and during season 2 campaigns to keep him at the hospital despite the fact that the Pediatric Chief Attending wants him gone, stating that he's a good doctor.
Hollywood Atheist: Claims to be 'Pagan' but demonstrates contempt for religion (specifically Christianity). He crosses himself in one episode which suggests he may have grown up Catholic, only to lose his faith later on.
Ladykiller in Love: He's established as the hospital stud in his very first episode. But in that same episode, it's also poignantly obvious that he's desperately in love in Carol.
The Unseen: Doug is mentioned as having come to Chicago to see his daughters and Carol at least once during season 6, but the viewer doesn't see his visit or his and Carol's exchange.
Played By: Sherry Stringfield
Chastity Couple: With Carter. Susan mentions in Secrets and Lies that they had yet to have sex, and she breaks up with him after realizing that he was obsessed with Abby and didn't feel that way about her.
Heroic BSOD: Had to see a therapist after she was forced to give her niece (who she was raising as her own daughter) back to her sister. In an earlier season, she also struggles with confidence issues after being blamed for a patient's death.
Noodle Incident: After her return. It seems like the viewer missed a few things, including her engagement to a real-life cowboy.
Parental Neglect: Her mother is rather aloof and self-absorbed and it's implied that Susan and her sister pretty much had to take care of themselves growing up, leading to the latter's problems. Her father initially doesn't seem to be much better, although he eventually steps up and offers to take care of little Susie at night whilst Susan goes to work.
Unresolved Sexual Tension: With Mark. According to Carol, Susan absolutely wanted Mark to come to Maui with her, but was afraid that he would be freaked out by the invitation. When he gets sick Susan takes care of him, which makes Carter (who didn't know Mark was sick again) rather jealous.
Some with Carter, when she left the first time. When she comes back, they get together but the relationship more-or-less fizzles because of Carter's obsession with Abby.
Abusive Parents: Of the severely emotionally neglectful type, to the point where not even him being nearly stabbed to death could make them cut short their vacation plans to be by his side. Their Freudian Excuse of still grieving his younger brother makes them slightly more sympathetic than most examples of this trope.
Chick Magnet: How many girlfriends did he have during the entire show, again?
Dramatically Missing the Point: When some of the hospital staff stage an intervention against Carter he challenges them to name one instance of him endangering patients' lives. Jing-Mei mentions how he sent a patient into anaphylactic shock by giving her a drug she told him she was allergic to. Carter then retorts that she almost killed a man by leaving a guide wire in his chest. Firstly, said incident took place practically six years ago, when Chen was a med student. Secondly, that incident was no indicator that Chen was starting to fall apart.
Heroic BSOD: After his friend Gant dies (heavily implied to be a suicide), after Lucy is killed (he clearly blames himself for both incidents), and after his son is stillborn.
Lucy's murder actually sends Carter over the edge and into drug addiction.
Last Name Basis: 15 years and you could probably count on one hand the number of times he was called by his first name, rather than his last. It's probably because Carter is a cooler name than the ordinary 'John'. Notably, Lucy Knight is the only regular character who ever only called him John (Kerry Weaver refers to him as John occasionally).
Likes Older Women: A good portion of his love interests were slightly (5-6 years) older than him. Chen makes note of this.
Nice Guys Finish Last: It took him forever to become an attending, and only was made Chief Resident after Chen was fired. It was even implied that once his residency was over, Weaver had no intention of hiring him, and only did so because of a shortage of Attendings. And this is after being forced to repeat his first year of residency due to switching specialties and then being told he is repeating his third year thanks to his drug issues.
Non-Idle Rich: Carter transfers to Emergency Medicine just to spend more time getting to know his patients. When Kerry says they might not have space in the budget for him, he nonchalantly says he doesn't need a salary, which surprises her.
Angry Black Man: To an extent. Peter is relentless in his abuse of Dennis Gant because he claims Gant, as a black man, has to work twice as hard to prove he's just as good as his white counterparts. Benton is also uncomfortable with dating Corday because she's white (largely because he's concerned about what his family might think) and resents Cleo's attempts to prove herself by being enraged at what she sees as prejudice, claiming that as a half-white woman she knows nothing about real prejudice.
Badass: Despite his personality flaws, Benton is generally a cool guy.
Daddy DNA Test: Twice. The first time Carla claims Peter may not be Reese's father. Peter goes as far as swabbing both him and Reese before telling himself and Carla that it's not important. The second time Roger challenges Peter's paternity (something Carla couldn't have done, as she put Peter's name on the birth certificate) and forces him to take a test. As it turns out, Reese's isn't Peter's biological son.
Heroic BSOD: Peter has many. When his mother dies, when he nearly kills a baby in surgery, when Gant commits suicide, when his son is born prematurely with severe complications.
Hypocrite: When it comes to racial issues. He claims that Cleo, as a bi-racial woman, doesn't understand the medical needs of the black community, even though he had an affair with Jeanie, who was half-white and was hired by him to take care of his mother.
When Carter transferred to Emergency Medicine. Benton told Carter that he should have come and talked to him instead of going straight to Anspaugh, even though when Carter actually came to Benton for advice on how to deal with Dale Edson (he falsified a chart, which is illegal) months earlier Benton simply blew him off.
Jerk with a Heart of Gold: Despite his brusque demeanor and often questionable bedside manner, he's very compassionate and wants the best for his patients.
Mama's Baby, Papa's Maybe: Peter is originally presented as Reese's father, but when Carla wants to take Reese with her and Roger to Germany she suddenly claims that there was someone else. Peter eventually finds out that he isn't Reese's biological father, but he decides that he doesn't care and will be there for Reese no matter what. The fact that Reese acknowledges Peter as his father is the deciding factor in Peter's custody case against Roger.
Papa Wolf: Most prominently to his son Reese, but also to Carter, his protege. He'd do anything for his son, ultimately quitting County so that he could spend more time with him, and when Carter was stabbed another patient almost died because Benton absolutely refused to leave Carter's side.
Token Minority Couple: Him and Cleo—the sole reason she was even created was to give him an African-American love interest.
Uptight Loves Wild: Deconstructed with him and Elizabeth. Aside from his uneasiness with their racial difference, in all likelihood the relationship would have failed anyway, as her vivacious, fun-loving personality was a stark contrast to his dour, aloof one.
Where Da White Women At?: Averted. Despite their mutual attraction, he's very reluctant to date Elizabeth because she's white and even after they do get together, his persistent discomfort, as well as his chronic self-absorption, causes the relationship to fizzle very quickly.
Breakout Character: To the point where she was supposed to have been killed off in the pilot thanks to a suicide attempt, only to be revived thanks to positive test audience reaction. The result is that she was essentially the show's heroine for the first 5-6 seasons and is the cast's sole Emmy winner—she even lampshaded this in her acceptance speech, cracking that "I was dead this time last year, now look at me."
Chuck Cunningham Syndrome: Doesn't appear at Mark's funeral—with zero explanation as to why—despite she and Doug being among his closest friends.
Dull Surprise/Emotionless Girl: She spent the year after Doug's departure acting very distant and detached—there is a visible change in her demeanor as she leaves the hospital, races through the airport, and is reunited with him in Seattle.
Heroic BSOD: Has one after accidentally killing a patient (she gave him the wrong blood). Her refusal to let the incident be covered up or used as an excuse to punish the other nurses (who were all having a sick day in protest at the time) nearly costs her her job. She has another after Doug leaves.
Law of Inverse Fertility: When she and Doug are a happy couple, they struggle to conceive. When he resigns in disgrace and leaves Chicago, they conceive twins.
One True Love: Doug. It's implied, but not explicitly stated, that Carol tried to kill herself because of Doug's adulterous behaviour (she broke up with him over his many affairs, but then slept with him a month before she tried to kill herself). When he leaves for Seattle, she claims she can't remember a time that she didn't love him.
Broken Bird: Despite her tough exterior there have been numerous instances where she has demonstrated herself to be really fragile underneath.
Chronic Backstabbing Disorder: Her modus operandi was basically to pretend to be someone's friend/ally before screwing them over in order to save herself. This was so prevalent that one of her victims outright said "I knew she was capable of this, I just didn't think she'd do it to me"
Defrosting the Ice Queen: Will often do something to prove to one of the the characters that she is genuinely a kind person underneath. For example, she demonstrates to Doug that she's actually very caring when it comes to children, she keeps Jeanie's HIV status a secret and then actively campaigns to keep her on staff when it's revealed, she lets Carter live in her basement and actually somewhat takes on the role of surrogate mother to him. However, she then follows up by doing something cold or horrible to them, making sure no one ever gets close to her.
Hypocrite: Countless instances of her criticizing people for doing things she had done or would do herself. Most notably, she tried to sabotage Doug's career advancement because he was such a cowboy, and yet almost as soon as he leaves she tries to circumvent a standing DNR order (because she thought the woman was her biological mother)—then months later hounds Mark for for doing the same thing, having the gall to insinuate that Mark isn't being objective because of the recent death of his mother, even though in this case, the patient had explicitly rescinded her DNR, telling Mark that she didn't want to die just yet.
Also when she pulls out all the stops to make sure Chen and Malucci are severely punished for their part in a patient's death—firing the latter and suspending the former, yet is just as vigilant in making sure that she herself incurs no punishment, even though as their supervisor, she bore the ultimate responsibility.
Inspector Javert: There were times when she was downright fanatical in her insistence that people adhere to rules and policy, not believing in making the slightest of allowances for any reason.
Karma Houdini Warranty: Kerry's double-dealing almost always puts her at the head of the pack, until toward the end of the show she finally made the mistake that cost her her career: her newest hire Dr. Clemente, though a genuinely talented doctor, was also an extremely violent paranoid schizophrenic. She's out the door a few episodes later. It's still really sad.
Mysterious Past: It took ten years to find out why she needed a crutch to walk.
Never My Fault: Rarely, if ever, saw her responsibility for whatever problems she had with other staff members and dumped the blame for a patient's death squarely onto the two doctors who treated him, conveniently ignoring the fact that as their supervisor, she should have been present to correct their mistakes, rather than off-site handling personal business.
The Peter Principle: With each promotion, Weaver proved herself unworthy of them, at least to the audience. Thanks to her Never My Fault tendencies, and the fact that she was such a Rules Lawyer when it came to subordinates that she was more than willing to find and highlight their mistakes over her own, she was rarely ever called out for this, and just kept moving up. Finally it came back to bite her, and she lost her job.
Sweeps Week Lesbian Kiss: Twice. Unlike most examples, however, this wasn't just a ratings grab, but rather part of a larger arc involving Kerry coming to terms with her sexuality. Both of the women she kissed appeared again.
Red Herring: As a pediatrician, there was speculation that she'd been brought on to be a new girlfriend for Doug—indeed, she initially seems very attracted to him. Only for Doug to reconcile with Carol as had been hinted at for weeks and Anna to be a love interest for Carter instead.
Straw Feminist: She tended to react to everything Doug said as though it was an attack or an advance, even though he was either just being friendly (asking her if she wanted something to eat after they'd both been on the streets looking for a runaway) or just offering his years of experience (offering to do a testicular exam on a patient because he might be uncomfortable with a woman doctor). Kerry Weaver seems to agree with her claim that Doug is threatened by women, but of course Kerry had been brow-beating and annoying him about publishing his thesis for his fellowship and just couldn't see that Doug (or anyone else for that matter) simply didn't want her help.
Nor it did occur to Kerry that Doug's problem was simply with her, given her abrasive personality and their constant clashes and nothing to do with her gender.
Heroic BSOD: Elizabeth treated a patient from Zambia who suffered from back pain, caused by a herniated disc. The patient didn't want open back surgery and Elizabeth had planned to go on a trip with Mark that evening so she suggested a less invasive procedure instead. The patient ended up paralyzed after leaking cerebral-spinal fluid and he sues Elizabeth for malpractice. The case eventually gets settled because the patient decided to sue the manufacturer of the surgical equipment instead, but Elizabeth continued to blame herself for the incident (even though the reason he was paralyzed in the first place is because one of the waldoes wouldn't grip the bone fragment in his spine) and promptly spent weeks avoiding the OR at all costs
Elizabeth has a break down during her wedding, making known her fear that Mark's tumour will return and her fear of him being hurt or ending up dead. Fears that end up being realised.
It Runs in the Family: Her mother and father are both scientists. Her father is a surgeon, her mother is a physicist.
One True Love: Mark, despite the character being introduced as a Love Interest for Peter Benton. Elizabeth's relationships before and after Mark all fail for one reason or another, in the latter case probably because of her love for Mark.
Someone to Remember Him By: Mark did manage to give her a daughter, and spend the first year of her life with her (long enough to hear her say her first words and see her learn to walk) , before he finally succumbed to cancer.
Played By: Kellie Martin
Audience Surrogate: Brought in because Carter, the previous audience surrogate, was now a fairly experienced and accomplished doctor.
Character Development: Despite her brief time on the show, she went from being a bumbling, clueless medical student, to a very competent one who would no doubt have been an excellent physician.
Cousin Oliver: It was explicitly stated that she was brought on to bring some new blood to the now five-year old series.
At Least I Admit It: For all his numerous flaws, as Cleo called him, "a racist, sexist, elitist jackass", there was no denying that he never once hid the fact that he was a colossal egomaniac who couldn't be trusted and whose primary concern was himself.
Flanderization: When he first appeared his bad traits were relatively low-key. The more often he appeared, the worse he got.
Hidden Depths: Adores his dogs, studies martial arts (as evidenced by him showing up at work in a karate uniform), is a member of the Polar Bear Club (he mentions it to Susan in one season 8 episode and a deleted scene shows him in a Speedo having taken one of the elderly members to the ER) and knows sign language.
He is also the only one to tell Corday to go back to Mark. This is especially a touching scene because Corday was probably the only woman he had genuine above-the-belt feelings for, and yet he told her to go back to her husband instead of attempting to use her moment of weakness to his advantage.
Pet the Dog: However rare they were, his Nice Guy moments were genuine. Even some of his supposedly Jerkass moments revealed that he was actually doing someone a favor—assisting a heavily pregnant Elizabeth with surgery, giving Peter time off to spend with his son, concern for the ailing Mark. Plus, the literal examples with his beloved animals, as well as his genuine fondness for Lucy Knight.
Earn Your Happy Ending: After everything Luka went through both before and after the series, he eventually got a happy ending with Abby and their son.
Heroic BSOD: Plenty of these for him too, all of which seem to happen just as things are getting better for him—he starts to recover from the loss of his wife and children by falling in love with Carol—then she leaves him. He starts to recover from this by dating Abby, then kills a mugger attacking them. One even happens out of nowhere then gets even worse after he almost kills a co-worker in a car accident.
Suspiciously Similar Substitute: A brooding hunk with allusions to a mysterious, tragic past and a not-so-secret longing for Carol? He was referred to as "Euro Ross" on many other fan boards (his resemblance to Doug didn't help much to dispel this). A period of promiscuity for him pretty much cinched it. Not to mention the fact that he fell in love with and eventually married Carol's effective replacement.
Unresolved Sexual Tension: With Carol. Especially bad as from his side of things, developing feelings for her was an indication that he was recovering from the deaths of his wife and children.
Younger Than They Look: Actor Goran Visnjic was 27 during his first year on the show. He easily could have passed for 40 and was immediately shown to be an authority figure (already an Attending) in the ER.
Dumb Jock: A doctor variant. Attended medical school in Grenada because he did poorly in college and on his MCATs.
Hidden Depths: Claims to have a child, although this may have been an appeal to Weaver's emotions.
Jerk With A Heart Of Jerk: Unlike Doug there's very little beneath that philandering Dumb Jock exterior. He's ultimately fired for having sex in an ambulance, with his one moment of depth (see above) being in his very last episode.
Kick the Dog: Malucci claims to have a child to support. Kerry fires him anyway. Later, Malucci's last mention on the series was Carter telling Gallant that he was reckless and killed a patient.
Pet the Dog: Despite his incompetence and the rest of the staff's utter contempt for him, Mark Greene seems to rather like Malucci and stands up for him when Kerry Weaver fires him. Perhaps it's because he reminds him of Doug.
Heroic BSOD: Has at least two. One after the infamous guide wire incident. Another for simultaneously giving up her son for adoption (she knew she could've easily taken care of him but was too concerned with what her overly traditional family might think) and for losing a patient and being back-stabbed by Kerry Weaver.
There's a sadder version several years later when she can no longer keep up with the demands of her job and caring for her ill father, especially when Susan tells her that she can no longer make allowances for her.
Suspiciously Similar Substitute: After Lucy Knight was killed, replaced her as the "bumbling & clueless" medical student. Then, though their personalities and backgrounds were vastly different, she replaced Carol Hathaway as the token nurse character once the latter left. (interestingly, when she first appeared on the show, she was precisely at the point Carol would have been in her medical studies had she decided to go to medical school)
Fourth Date Marriage: He expressed interest in Neela but was shipped off to Iraq before ever getting to officially ask her out. From then on, their courtship takes place via letters and e-mails. It's not known if they ever even HAD a proper date before he returns on leave and proposes to her, with them marrying very soon afterwards before he's sent back. This is acknowledged when shortly after they've married and Gallant is preparing to return to Iraq, much to Neela's dismay, she admits, "I love you, but I don't *know* you".
Character Development: Probably the most extensive in the show's history. Started out as an annoying, bumbling, incompetent fool who no one liked. Ended as one of the best doctors in the hospital whom everyone respected.
Carter: Looks like you followed my advice, Archie.
Evil Brit: Not so much evil, but definitely Jerkass, initially. And Australian rather than British, but there is definitely an "Evil Token Aussie" trope which is less common than Evil Brit but still seen sometimes on American TV.
Belligerent Sexual Tension: After weeks of being at each others throats, he and Neela get into a full-fledged shouting match, which of course culminates in them going at it.
Why Did It Have To Be Spiders?: Had a fear of dead people early on in the series. Also afraid of thunderstorms, although the latter seems to be justified.
Commuting on a Bus: Appeared regularly up until Season 4, disappeared for a bit in the middle of Season 4 (was moved to nights due to accidentally blowing up the ambulance bay), then left at the end of Season 5 for unknown reasons. Returned again during Season 8, left again during Season 13 and returned partway through Season 15. The Season 13-15 absence was Lamp Shaded in show as Jerry "slinging beers in Alaska" which was a reference to Benrubi's character on Men In Trees.
Gentle Giant: Was used as a bouncer of sorts on occasion, but never really got violent with anyone.
New Powers as the Plot Demands: Became a Minister when Neela and Gallant were due to get married and became the ER's ASL interpreter partway through Season 12. None of these had been brought up prior to when they were needed and in the case of the ASL, he had never been shown signing to anyone on staff, let alone teaching Benton. It is possible that he learned after Peter's departure, but it's never really made clear.