After poisoning Lincoln, Rebecca March tells him that although the Electrum in his body will eventually revive him, by her calculations it won't be until after he's been interred in the ground, leaving him alive and conscious in his grave indefinitely.
And naturally, this is what it's been like for Brody the past several days in the coffin where his parents left him on the hidden thirteenth floor of the March building.
Both Sides Have a Point: In Carrie's argument with her mother before leaving home to help the others infiltrate the Court of Owls celebration dinner. Carrie argues that she's doing this to save a greater number of lives, while Doctor Kelley is terrified that she'll be left alone and bereaved like any number of other mothers she's had to break the news to that their children were killed. (This is an especially relevant concern for an African-American mother, given how many African-American people are killed while doing nothing at all, let alone going out to do heroics.)
Card-Carrying Villain: When a dying Lincoln calls Rebecca "pure evil", she doesn't deny it. Nor when Harvey calls her "cruel and twisted".
Conscience Makes You Go Back: After seeing on the news that the entire group has been arrested, Duela tells her mother that she's going to go back and rescue them. Unfortunately, Jane drugs her instead.
Continuity Nod: Brody apologizes to Turner for being a jerk to him in the pilot over not realizing that his dad was Batman, given that he didn't realize his own parents were the heads of a murderous cult.
Darkest Hour: The Gotham Knights and Brody have been apprehended by GCPD, Duela gets drugged by her mother, Harvey is taken to who knows where, and now Rebecca has sent the Talons to kill the Gotham Knights while they're in jail.
"Eureka!" Moment: Turner has one when he realizes that if Alan Wayne put a secret thirteenth floor into March Tower, he probably put one into Wayne Tower as well and that the Talon who killed Bruce had made use of it.
Rebecca claims that she started out manipulating Harvey but fell in love with him for real, causing her to pivot to setting up Lincoln instead.
It's unclear if Rebecca gave Electrum to Brody because of this or just as an experiment.
Frame-Up: As she knows the Knights are on the verge of exposing the Court's existence, Rebecca takes steps to make sure she won't go down with the ship by massacring all the other Court members so that the police will find the Gotham Knights with their dead bodies and hold them responsible.
The Friend No One Likes: Turner is the only one who insists Duela is still part of the team and should be given another chance, and doesn't believe she was in on Jane Doe's plan to give him to the authorities; Harper and Cullen in particular are eager to wash their hands of her now that she's joined up with her mother.
Friends with Benefits: Harper says that Duela and Turner are "fugitives with benefits".
Hidden Depths: In contrast to the above, it turns out that Duela likes the other Gotham Knights more than she let on, being visibly upset that all of them have been arrested by the police, including "Little Bird" (Robin).
The Knights learn that the text Stephanie received was faked and Brody didn't go into hiding, as one of Robin's devices receives a low power alert from the lapel camera Turner used to record the Court several episodes ago, which the text had claimed Brody destroyed.
Duela learns from Turner that Jane drugged him and left him for the police to find last episode.
The Knights learn from Brody that Rebecca is the true leader of the Court of Owls, and Harvey learns it by finding articles about Doctor Rebekah Leviticus on the thirteenth floor of Wayne Tower.
The police sergeant Cullen befriended while impersonating a cop in past episodes learns who he really is when he's brought into the station with the others.
Leave No Survivors: At the end of the episode, Rebecca commands her Talons to kill all of the Gotham Knights who are in prison.
Loving a Shadow: Harvey tells Rebecca that the her he fell in love with was just an illusion and he could never love the person she really is.
Mythology Gag: Harper refers to "spoiling" the Court's dinner when speaking to Stephanie, again referencing Steph's comic book codename Spoiler.
Rebecca tries to claim the people she killed while creating Electrum were all outweighed by the millions who could live due to it when speaking to Harvey. He scoffs at this, disbelieving she's ever done anything for the sake of other people, and she instantly drops this as her excuse.
Carrie's rationale to her mother for risking her own life to save others.
Night of the Living Mooks: Rebecca uses Electrum to reanimate all the deceased Talons from previous generations as her new mook army.
Rebecca March is really Mad Scientist Doctor Leviticus (who was not a man as the Knights assumed when they read about Leviticus's research), is over two hundred years old thanks to Electrum, and was once engaged to Alan Wayne. She tells Harvey that she's started over with a new name and family many times, indicating that Lincoln is not the first husband she's had, and Brody may not be the first child she's had, either.
The Talon was able to sneak up on Bruce and go unseen by security cameras because Rebecca knew that Alan Wayne put hidden thirteenth floors into all his buildings, including Wayne Tower.
Brody revived after being stabbed because Rebecca had Electrum put into his tooth. No doubt that was what his dental surgery a few episodes ago was all about.
Lincoln has also taken Electrum. The other Court members had not yet, though, as that was what the ceremony tonight was supposedly going to be for, and will stay dead.
Speaking of the other Court members, the Knights find that they include half the city council, and Gotham Academy's president. Carrie humorously says that that last one makes perfect sense.
Sixth Ranger: Brody joins the team after Stephanie and Harper rescue him. Since Duela is off the team at the moment, he is literally the sixth ranger, too. Duela is annoyed that the others "replaced her with a jock".
Took a Level in Badass: Stephanie now has Action Girl status in her and Harper's fight against the guards in March Tower; she lampshades that she's been training since her last fight (when she fought the drug dealers in the gym with the others and had to be rescued by Harper).
Truth in Television: Part of why it's not a big challenge for Harper and Stephanie to disable the Owl guards in March Tower is that the guards hold their guns very close to their targets, making the guns easy to grab, which most real-life professionals would know not to do. Additionally, the guards most likely underestimated two teenage girls and didn't think they would be much of a threat.
We Can Rule Together: Rebecca to Harvey, offering for him to "wield the power he deserves" with her. He rejects her, saying that no part of him could ever love someone like her. She tells him not to be so sure about that and has her mooks drag him off somewhere, implying that she thinks she'll have more luck if she draws out his other persona.
Wham Shot: Harvey finds a picture of Dr. Leviticus...who's Rebekah.
Xanatos Speed Chess: Rebecca cites this as one of her own specialties, saying that she always "pivots".
