The one with a man who looks suspiciously like a young Yondu.
Written by Jamie Mathieson.
The Doctor has grown restless over the decades, (mostly) keeping to Earth and watching over the Vault and its mysterious occupant. On the spur of the moment he suggests a "camping trip" and brings up a map on the TARDIS for Bill to pick the location — and then he notices one location on the map that is sending a distress signal, a space station of the far future. Wanderlust and a call to help? How can the Doctor resist, even as Nardole and Bill do — all the more as it becomes clear that Chasm Forge is a most dangerous place?
This is a mining company rig where the crew members are being murdered one by one. They are being stalked and killed by none other than the corpses of those who died before them, who still walk thanks to their "smartsuits". And there is more. Oxygen is a most precious commodity in the depths of space, and there's little "licensed" oxygen left within the station; everyone must wear smartsuits to survive inside and outside, and the oxygen supplies of these are running dangerously low. Their only hope seems to be to find a place that can isolate them from their pursuers where they can wait for rescue, but is there anywhere left to hide?
The Doctor must save whomever he can on this doomed rig, but that is not his only responsibility. He knows that he must keep Bill and Nardole, who never asked for any of this, who pleaded with him to turn back, safe and alive... no matter what the consequences might be for him.
- Allergic to Routine: The Doctor, after seventy-plus years stuck on Earth, is itching to go back having adventures in space to the point he deliberately seeks out a distress call.
- Anguished Declaration of Love: Or in this case, an anguished declaration of I Want To Have Children With You. Unfortunately her commlink shuts down at that point.
- Animated Armour: Shortly after our heroes arrive, they find a person in a spacesuit stacking crates. It's shortly revealed via the removal of the helmet that it's just a spacesuit, with no one inside.
- Artificial Gravity: Discussed — Bill, when told the station has it, tests it by jumping up and down.
- Artistic License Biology: The station's passageways are measured in "breaths", not linear distances. But human breaths' size is not constant: it varies slightly between individuals, and drastically depending on how much the breather is exerting their muscles. That said it is described as "Average Breaths," presumably based on a calm average human.
- As the Good Book Says...: The Doctor of all people quotes Corinthians 15:55 when he says, "Death, where is thy sting?"
- Awesome Mc Coolname: Mining Station Chasm Forge.
- Badass Boast:
- When the Doctor is asked who exactly he is:The Doctor: I'm the man who's going to save all your lives, and you're going to spend the rest of them wondering who I am.
- Being blinded doesn't stop him either.The Doctor: Bill, I've got no TARDIS, no sonic, about ten minutes of oxygen left, and now I'm blind. Can you imagine how unbearable I'm going to be when I pull this off?"
- When the Doctor is asked who exactly he is:
- Batman Can Breathe in Space: None of the survivors are sure how the Doctor survived loaning his helmet to Bill in the middle of a vacuum for as long as he did, not being aware of his body's respiratory bypass system. Even so, the experience leaves him blind, and their attempt to fix it at the end of the episode turns out to have failed.
- Battle Discretion Shot: As Bill is fading in and out with oxygen deprivation, she has glimpses of weapons fire, waking up inside the space station after it's all over.
- Being Good Sucks: To save the "expendable" members of the space station, the Doctor has to risk not only his life but those of his reluctant, upset friends, and ends up blinded for his trouble.
- Been There, Shaped History: A future version — turns out by rescuing two witnesses to the company's action, a revolution started that overthrew the corporate rule of space.
- Beware the Silly Ones: Nardole, who up until this point in the series has been pretty much just comic relief, goes absolutely ballistic at the Doctor after they return to Earth for risking their lives and coming close to dying, potentially leaving the occupant of the "vault" unguarded.
- Bittersweet Ending: The Doctor manages to stop the deaths in the end, but out of the forty-strong crew of the station and the four who were alive when he arrived, only two make it to the end. Worse, the Doctor is blinded in the process. Not only is his job guarding the Vault now more difficult, but he's lied to Bill about his condition, presumably to spare her feeling guilt.
- Blind Driving: Though only apparent in retrospect; the Doctor pilots the TARDIS to corporate headquarters, and then back to Earth apparently without a hitch. Presumably the TARDIS is helping him, and his Photographic Memory means he'd know the position of every control. What's more impressive is how the Doctor rewires an unfamiliar reactor while blind, while simultaneously locking the crew out of the computer so they can't interfere.
- Brutal HonestyBill: What if you're wrong?
The Doctor: Well, we'll be horribly murdered.
- Call-Back: Nardole attempts to ground the TARDIS by removing fluid link K57, which the Doctor has told him the TARDIS can't fly without; the Doctor then flies the TARDIS off anyway and reveals that he was lying about the effects of removing the link. This situation echoes one all the way back in the very second story of the Classic series, where the Doctor sabotaged a fluid link to force the characters to explore Skaro, though in that case he was sincere about the TARDIS not being able to fly without it.
- Capitalism Is Bad: As the official episode summary reads: "the TARDIS crew battle for survival against the darkest evil of all." The Doctor makes numerous derogatory comments about capitalism and the idea of controlling oxygen on a spaceship for profit throughout the episode. At the end, he alludes to the fact that what happened aboard Chasm Forge will serve as a catalyst for a rebellion which leads to capitalism's downfall... until humanity finds another great mistake, but that's another story. The "capitalism" in this story isn't the watered down post-unionization modern version either, it's full-out Robber Baron stuff.
- Captain Obvious: Nardole points out that the TARDIS is on the other side of a sealed door and opening it will expose everyone to the vacuum of space, sending the Doctor into Sarcasm Mode. In fairness, the Doctor looks like he's trying to get the door open at the time.
- Celebrity Paradox: In the episode prologue, the Doctor quotes the famous "space, the final frontier" narration from Star Trek, which would indicate that the Star Trek franchise exists in the Whoniverse (and lest we forget, way back in Series 1, Rose told the Ninth Doctor to "make with the Spock!" already). Several actors have appeared in both Doctor Who and Star Trek, including Noel Clarke (who played Mickey in the first four seasons of the revival series and had a supporting role in Star Trek Into Darkness) and Simon Pegg (who was the Editor in "The Long Game" and plays Scotty in the rebooted Star Trek film series). And if you accept the graphic novel Star Trek: The Next Generation/Doctor Who: Assimilation² as canon, two previous Doctors have met the crew(s) of the Enterprise.
- Chekhov's Gun: Bill has numerous problems with the suit she got from the repair shop. It's later revealed, after her suit shuts her down, that its battery is running low and thus couldn't give her a fatal shock.
- Chronic Hero Syndrome: The Doctor initially just wants a change of pace from present-day Earth, but he specifically decides to travel to a distressed space station — even though he's supposed to be guarding the Vault and could put the station off until later (due to the nature of the TARDIS) — not only because he can't resist a mystery but it's just not in his nature to ignore those in need. Even Bill and Nardole's reluctance and pleading can't turn him away. He rescues two members of the station, keeps Bill and Nardole safe from harm, and the Vault situation is unchanged. But he winds up blinded for his trouble; from here on out his guarding of the Vault back on Earth will be more difficult and could lead to great grief for all of Earth.
- Cold Equation: Played with when it looks like Bill has been abandoned when her suit refuses to move. The company who runs the space station pull their own version when they decide to Kill 'Em All to save profit.
- Completely Off-Topic Report: The Doctor delivers a lecture on all the ways that space can kill you to a packed lecture theatre. It was supposed to be on crop rotation.
- Consummate Liar:
- Nardole knows the TARDIS fluid link is needed to fly the TARDIS, so he removed it. How does he know the fluid link is needed to fly? The Doctor told him; he was lying. Nardole, somehow, did not see that coming.
- Nardole demands the Doctor tell him the truth. His response?The Doctor: Don't be unreasonable.
- Continuity Nod:
- The Doctor's lecture on the dangers of space was supposed to be on crop rotation, referencing back to Bill's mention early on in "The Pilot" that the Doctor tends to lecture on whatever he wants, and frequently changes topic unannounced.
- This isn't the first time someone's jumped up and down to test the gravity.
- Nor the first time a companion has realised the Doctor's joking is just him trying to cover up a very bad situation.
- The Doctor remarks that fear keeps you fast.
- This isn't the first time the Doctor's dropped off two survivors of a disaster at a mining facility at corporate HQ so they can try and change things.
- This is the second time the Twelfth Doctor's suffered Redemption Equals Affliction: To fully return from the Despair Event Horizon that turned him into a Woobie, Destroyer of Worlds after Clara Oswald died, he had to lose his personal memories of Clara. Now, because his Chronic Hero Syndrome put Bill and Nardole in danger and he had to give her his space helmet to keep her alive, he's blind.
- Continuous Decompression: When the "unlicensed oxygen" that was brought on board thanks to the TARDIS is purged from the station. The Doctor manages to close the door before he, Bill and Nardole are blown out, but they're cut off from the TARDIS.
- Corrupt Corporate Executive: The unseen villains of the episode. They're using the suits to murder the crew of the Chasm Forge, whose "inefficency" and reduced productivity have made keeping them alive more trouble than it's worth.The Doctor: We're like workers everywhere. It's us against the suits.
- Darkness = Death: Bill and Nardole really don't want to go down the dark corridor to investigate the mysterious banging sound, until the Doctor points out there are people still alive on the station who need rescuing.
- Dead Hat Shot: Ivan realises his wife has just died when he sees her space helmet drifting past.
- Deadly Euphemism: Deactivate your organic component.
- Destruction Equals Off-Switch: The Doctor smashes the door control to stop the suits following them. Turns out they're smart enough to repair the damage, so the reprieve is only temporary.
- Distress CallThe Doctor: That is my theme tune. Otherwise known as a distress call.
Bill: You like distress calls?
The Doctor: You only really see the true face of the universe when it's asking for your help.
- Do You Trust Me?: The Doctor when he tells Bill he's going to leave her behind.
- Dramatic Space Drifting: The episode opens on two dead bodies tumbling through space.
- Due to the Dead: Bill is freaked out by the dead body standing in its suit. The Doctor and Nardole don't seem to understand why she'd prefer it to lie down.
- Episode of the Dead: An episode with zombies IN SPACE! Well, technically AI-controlled spacesuits with dead corpses inside, but still count as zombies.
- Eureka Moment: The Doctor has one when he realizes why the suits killed their wearers, and simultaneously that Bill's suit won't be able to kill her.
- Evil, Inc.: Chasm Forge is a corporation that has no problem in "deactivate" employees instead of fixing what's wrong and so keep resources.
- Evil States of America: "Velma", the ship's AI, speaks in an American accent, making it likely that the malevolent bosses are also American.
- Exact Time to Failure: The suits list how many average breaths you have left. Not the time you have left, because you breathe faster under stress, say if you're being pursued by your dead colleagues in those same suits...
- Exact Words: Nardole demands the Doctor look at him while he's giving "The Reason You Suck" Speech. The Doctor can't. Not because he's ashamed or refusing to listen. Because he's still blind.
- Explosive Decompression: Averted in great detail. The episode opens with the Doctor describing the physical effects of vacuum exposure. Later in the episode, Bill is exposed to the vacuum of space and loses consciousness in fifteen seconds, but does not explode.
- Eye Motifs: Continuing a major motif of Series 10, the Doctor is blinded in this episode and the ending reveals he cannot cure his condition.
- False Reassurance:
- The Doctor, constantly.The Doctor: Err, nothing to worry about.
The Doctor: Yes, not for several minutes.
- The Doctor examines a short-circuited suit.The Doctor: It's fried, should be safe.
Nardole: Err, you thought you were safe before.
The Doctor: Yes, well, I'm bound to be right eventually, aren't I?
- The Doctor, constantly.
- Fantastic Racism:
- Bill is accused of it by Dahh'Ren, the blue-skinned alien miner, when she's surprised by his appearance. She's just beginning to win him over when he becomes the suits' latest victim.
- Inverted when Dahh'Ren is puzzled as to why Bill would be on the receiving end. Apparently some kinds of discrimination have been replaced by others. Nardole assures him that some of his friends are blue.
- Bill keeps Digging Herself Deeper when she's confused as to why the alien is called Darren. It's actually Dahh'Ren.
- Five-Second Foreshadowing: When Nardole is chewing the Doctor out for putting himself in danger, shortly before the Doctor reveals he's still blind, he's wearing dark glasses indoors, like a lot of blind people. He also messes up his yo-yoing.
- The Doctor pops the head off the robot suit without alerting his companions what he's about to do. Later he also fails to fill them in on his plans, but this time he has a good reason.
- When Bill comes to after the trip outside the station, she's told that the Doctor gave her his helmet, and that he paid the price for it. The ominous tone comes off as if the Doctor had to regenerate as a result, although that turns out not to be the case. And when Bill learns he was blinded as a result, he says he needs to get back to the TARDIS because there's stuff in there that can fix it — and the TARDIS is where he usually regenerates...
- During his "The Reason You Suck" Speech to the Doctor at the end, Nardole says that if the Doctor came back injured, the prisoner in the Vault would be able to detect it. Then the Doctor reveals he's still blind...
- Freudian Slip: The Doctor gives a lecture on space when he should be talking about crop rotation. Nardole correctly surmises that he's thinking of haring off into space again.
- From Bad to Worse: The Doctor loses access to the TARDIS, his sonic screwdriver gets destroyed, and now he's blind.
- The Gadfly: The Doctor establishes that the robot suit is empty by popping its head off with the sonic screwdriver, startling the hell out of Bill and Nardole. When they complain, the Doctor just says that adrenaline is good for them.
- The Glomp: Bill hugs the Doctor when she realises he sacrificed his eyesight to save her.
- Go Look at the Distraction: This time the Doctor sent Nardole to Birmingham for a pack of crisps.
- Go Ye Heroes, Go and Die: Only the Doctor could actually give a Rousing Speech encouraging people to blow themselves up, and have it work!
- Group Hug: Nardole joins the Doctor hugging Bill, much to his annoyance.
- Handicapped Badass: The Doctor, despite being blinded, still manages to save the day, delivering a Badass Boast about who he is and what he does right before he does it.
- Have a Nice Death: "Please remain calm while your central nervous system is disabled. Your life is in our hands."
- He's Dead, Jim: The Doctor with the first corpse. Admittedly its face was frozen over.
- Heroic Sacrifice: The Doctor saves Bill from asphyxiating in space; because he has to endure the void as a result of giving her his helmet so she can breathe, he goes blind.
- Hiding the Handicap: The Doctor, after his eyes were apparently fixed, reveals to Nardole that he is hiding blindness at the end of the episode.
- Hypocritical Humor: When Nardole reveals he stole the fluid link to stop the TARDIS from moving, the Doctor chides him for being untrusting... before revealing that he was lying about the fluid link immobilizing the TARDIS.Nardole: You took an oath, sir. The Vault cannot be unguarded.
The Doctor: Oh, listen to Mister Boring.
Nardole: I'm acting under your orders!
The Doctor: See how reliable I am?
- If We Get Through This...: The woman at the beginning who is killed by her suit tries to tell her co-worker shortly before it happens that she loves him and would like to have a baby with him if they get off the station.
- I'm Standing Right HereThe Doctor: You really think this is going to slow me down? I do most of my best work ordering other people around.
Dahh'Ren: You do know we're still here, right?
The Doctor: Didn't I send you out to get me a latte?
- In Harm's Way: After lecturing on how dangerous space is, the Doctor not only insists that Bill join him for an adventure there, he turns down her first suggestion as too boring and has them investigate a distress call instead. Nardole rightly rips into the Doctor for this cavalier attitude when he's got serious responsibilities on Earth.
- In Space, Everyone Can See Your Face:
- The suit helmets have clear glass faces. However, the Doctor, Bill and Nardole's early run-in with an empty suit stacking boxes suggests that the visors can be tinted.
- Helmet forcefields are used to prevent the actors having to spend the entire episode inside a helmet. Handwaved as the forcefields not being substantial enough to withstand a total vacuum.
- Insufferable Genius: The Doctor.Bill: Do people ever hit you?
The Doctor: Only when I'm talking.
- Bill gives a bitter laugh on seeing a poster: LOOK AFTER YOUR SMARTSUIT AND IT WILL LOOK AFTER YOU.
- Ivan finds himself being handed a replacement oxygen cylinder by his dead wife. He can only mutter, "Thanks."
- It Can Think: The suits have a "basic problem-solving AI", which turns out to be quite up to solving the problems presented by jury-rigged locked doors and incomplete maps.
- It's All My Fault: When the Doctor and Nardole have to leave Bill behind, presumably to her death, the latter tells the former it wasn't his fault. But although this is actually part of the Doctor's plan to save her, he blames himself for all the trouble because he was the one who insisted on figuring out what was wrong with the space station and pressed her and Nardole to follow him.
- The Lancer: Abby is openly hostile to the Doctor, while Nardole spends much of the episode in Sarcasm Mode. Bill lacks the experience to realise she needs to be equally wary of him.
- Lecture as Exposition: The episode opens with a lecture from the Doctor on the dangers of the vacuum of space (it was supposed to be on crop rotation), and Bill gets to experience some of them first-hand when her helmet malfunctions. One danger he mentions that often gets passed over is the fluids of the eyeballs boiling. He later blinds himself by travelling through the vacuum without a helmet after giving Bill his.
- Like an Old Married Couple: The Doctor and Nardole just can't stop bickering! When they do in fact stop, events have turned deadly serious.
- Literal Metaphor: "Like every worker, everywhere, we're fighting the suits."
- Mistaken for Racist: Bill, due to her reaction when meeting a blue-skinned alien. It's a novel experience for her because she's usually on the other side of discrimination.
- Mood Dissonance: Velma's cheery voice in Bill's spacesuit. She'd really prefer to shut it off, but the mute button is damaged.
- Motifs: Several Series 10 motifs continue apace:
- "Villains" who aren't evil: The "zombies", who walk and stalk because of the programming of the smartsuits.
- Exploitation: The smartsuits are designed to kill their wearers if they aren't efficient enough for the company that employs them.
- Mothers: The first on-screen victim wants to be one; Bill sees the picture of her mother in her mind's eye as she has her near-death experience.
- Hidden threats: The suits the workers think are for protection are actually what's killing them.
- Swarming creatures: A variant: The smartsuit victims travel in a pack.
- Imprisonment/Release: The episode ends with Nardole discussing the prospect of disaster for Earth if the Doctor doesn't guard the Vault and its prisoner properly, noting that he needs to be ready when it opens, suggesting a release is imminent.
- Promises: The Doctor promises Bill that he will be waiting for her on the other side when she walks through hell.
- Truth: When Nardole asks the Doctor for the truth early on, he replies "Don't be unreasonable." Later, he tells Bill and Nardole why they will explore the space station despite the risks: "The universe shows its true face when it asks for help. We show ours by how we respond." At the end, he reveals to Nardole that despite what he's let on to others, he is still blind.
- The value of each individual life: The Doctor is not only determined to save whomever he can on Chasm Forge, but equally — if not more — determined to keep Nardole and Bill safe. He ends up losing his eyesight in the process of saving Bill from asphyxiation.
- Murder Is the Best Solution: Faced with loss of productivity, the owners of the Chasm Forge decide to kill and replace the entire workforce, rather than upgrading equipment or sending in a new manager.
- My Life Flashed Before My Eyes: Played with; Bill has a flashback of putting up the picture of her mother in "Knock Knock", the only memory she has of her.
- Noodle Incident: Nardole apparently got his current face after having to go on the run.
- No OSHA Compliance: Justified; the station was built by a penny-pinching corporation that's prepared to execute its workers to save money. Airlocks and spacesuits with failsafes to protect the workers are the last thing they'd think of.
- Off-the-Shelf FX: The inputs to the suits are unmodified powerCON connections, quite recognisable if you've ever worked in the lighting/AV industry.
- Oh, Crap!:
- Our heroes when they realise the station is about to purge the air bubble from the TARDIS.
- Nardole switches on the outside lights to reveal the hull swarming with suit-zombies.
- The Doctor, when the sonic screwdriver is destroyed by the occupied suit in the repair shop.
- Bill and the Doctor, when her malfunctioning suit removes her helmet in the airlock while it's cycling so they can go outside.
- Bill, when the others have to leave her behind because her suit won't move.
- One-Word Title: "Oxygen".
- Only Mostly Dead: It turns out Bill's suit didn't have quite enough power to kill her.
- Our Doors Are Different: The Doctor prefers the Used Future look.The Doctor: Look at this. Classic design. Pressure seals, hinges. None of that shk-shk nonsense.
Nardole: Space doors are supposed to go shk-shk, not urrrrr.
- Our Zombies Are Different: In this case they are dead people inside AI-controlled spacesuits. As per usual for zombies however, they create more of themselves each time they kill.
- Pride: When the blinded Doctor stumbles over something, Bill goes to help but is stopped by Nardole, who explains that the Doctor really doesn't want any help.
- Paying for Air: The corporation controlling Chasm Forge also controls its oxygen supply, and has passed rules rationing it to employee's personal spacesuits only. When the TARDIS brings some extra oxygen on board, the A.I. controlling Chasm Forge complains that the oxygen wasn't sanctioned by corporate and vents it into space to "keep prices competitive".
- Prophet Eyes: The Doctor, after being blinded, has mostly white eyes. It is in this state that he "sees" the true nature of the crisis.
- The Radio Dies First:
- Rapid-Fire "No!": Ellie as she's about to die, followed by a Big "NO!" from her husband when he realises what's happened.
- "The Reason You Suck" Speech: Nardole gives the Doctor a pretty blistering one for risking everyone's lives and coming close to getting them all killed, which would have left the Vault and its dangerous occupant unsupervised.
- Redemption Equals Affliction: A heroic "really screwed up" example. The Doctor manages to save Bill after dragging her into the crisis at the space station when both she and Nardole would rather have left, but it comes at the expense of his eyesight.
- Robosexual: Nardole recognises the voice of Bill's suit as belonging to an actress he used to date. "Left me for an A.I. in a call centre."
- Saying Too Much: Nardole mentions they're in Section 12, so the suit-A.I. realises there is a section not included on its map. This is why the Doctor refuses to explain his own plan, realising the A.I. will overhear.
- Spacesuits that still walk after the occupants die appear to be one to the trauma override harnesses from Fallout: New Vegas. The harnesses were themselves the source of a shout out when they repeatedly asked "Hey, who turned out the lights?"
- The Doctor's opening narration begins "Space, the final frontier." Furthermore, walking zombie-like beings that form a cybernetic Hive Mind, can survive in space, and claim their victims by touching them? Sounds familiar to any Trek fan.note
- The spacesuits have a red light on the front that looks like HAL.
- Bill's spacesuit has a Microsoft Office Assistant moment: "You look like you're trying to run. Would you like some help with that?"
- Slave to PR: The Doctor says that if the station was destroyed by a core meltdown, then the resulting explosion would be visible to large sections of the current galaxy. Nothing says shareholder panic like "your station exploded".
- Smash to Black: At the very end of the episode. Used to brutal theatrical effect here to demonstrate the total darkness the Doctor is currently stuck in.
- Some Kind of Force Field: The helmet forcefield is demonstrated when Nardole pokes the standing corpse.
- Space Is Cold: Bill's breath fogs up when her spacesuit helmet accidentally comes off in a vacuum.
- Space Jews: Implied about Dahh'Ren's species when Nardole says "some of my best friends are bluish". (Though admittedly it could just be a bad pun.)
- Space Station: Mining Station Chasm Forge.
- Subverted Catchphrase: Though not for this series.The Doctor: Space, the final frontier. Final because it wants to kill us.
- Taking You with Me: Threatened by the Doctor. Realizing that the employees were killed just to save money, he rigs up the station to be destroyed if the remaining ones die, making them more valuable alive than dead.
- Temporary Blindness: The Doctor gets blinded after having to give Bill his helmet so she could travel outside the space station. He says that there's medical equipment on the TARDIS that will be able to fix it up. The last line of the episode subverts it, however — he's still blind, and faking being able to see.
- Tempting Fate: Holy crap. Firstly, we have the Doctor's highly disturbing lecture on space medicine, specifically graphically detailing exactly how sudden exposure to hard vacuum kills you. Delivered with what can best be described as morbid glee. Second, he slips in a "fun fact": that exposed body fluids, including the liquid around your eyes, will start to boil. Third, refers to distress beacons as his "theme tune"...
- That's What I Would Do: Nardole's response when it's suggested that the suits were hacked to kill off the crew before a robbery. Everyone stares at him. He quickly backpedals.
- Think Nothing of It: Addy, the most skeptical member of the survivors, apologizes once the Doctor saves their lives. Unusually for the egotistical Doctor, he gives this trope. It's not false modesty; he's covering for the fact that he's still blind.
- Touch of Death: The compromised suits can upload the termination command to the off-network ones through physical contact, and the command immediately kills the wearer and takes over the suit.
- Unspoken Plan Guarantee: The Doctor doesn't reveal his plan to anyone, in part because the spacesuits' AI might overhear. It goes off perfectly.
- We Would Have Told You, But...: The Doctor doesn't tell Bill that she'll be okay, or what his plan is, when he's forced to leave her behind because the suit's AI would have overheard.
- Wham Episode: The very last lines mark this as one, revealing that the Doctor was permanently blinded over the course of its events. This event will significantly impact the following episodes.
- Wham Line: At the end of the episode, when all seems well and the Doctor was playing with his yo-yo just moments ago...The Doctor: I can't look at anything ever again. I'm still blind.
- What You Are in the Dark: The Doctor cites this trope, stating, "The universe shows its true face when it asks for help. We show ours by how we respond."
- Why Isn't It Attacking?: Bill revives from her oxygen-deprivation to see the suits walking past the open door without entering. Turns out this section hadn't been added to the AI's map of the space station, so the suits just think there's nothing there. Until Nardole tells them otherwise.
- Who Are You?: The Doctor responds with a Badass Boast, saying he's going to save them so they'll spend the rest of their lives wondering about who he was and why he saved them.
- The World Is Just Awesome: Averted; the episode starts with the Doctor explaining why outer space is dangerous, and the rest of the episode demonstrating it.
- Wrecked Weapon: A suit crushes the sonic screwdriver, short-circuiting the suit but depriving the Doctor of his iconic Deus ex Machina.
- You Have Outlived Your Usefulness: The suits are programmed to exterminate their wearers because Chasm Forge's mining operation has become unprofitable. The suits can keep doing the work while the useless humans stop wasting oxygen that the company can resell.
- Zombie Gait: As the suits are doing the walking, not the bodies.