“Boom” puts the Doctor’s foot on a live landmine in the first five minutes and keeps it there for the rest of the runtime, and everything else in the episode has to work around that one immovable fact. It’s the best hour of the Gatwa era so far, and I loved it. It’s tense, it’s angry and it has a proper idea underneath it. It does all of that with the lead character standing still.
That constraint is the whole design. He can’t run, can’t fiddle with a console, and can’t do the thing this show usually does where the Doctor solves a problem by moving faster than everyone else. Take away the running and you find out what’s left, which turns out to be a man talking very quickly while terrified. It’s also cheap in the best way: one quarry, some smoke, a handful of actors and a glowing disc on the ground. The most effective hour of the most expensive series this show has made is the one that spends almost nothing.
The mine is brilliantly built
The rules are set quickly and never bent. Step off and it detonates, shift your weight and the tolerance narrows, and the mine judges the threat level of the person standing on it, so panic makes it worse. It’s a machine that punishes exactly the reactions anyone in that situation would naturally have. What lifts it from a gimmick to a premise is that the mine is a product. This is Villengard, an arms company that makes the weapons, the war and the ambulances, and the mine is governed by an algorithm tuned for casualties because casualties are the business model.
That’s a genuinely furious idea, and the episode never softens it. The war on this planet has no enemy, just soldiers fighting an opponent that doesn’t exist, kept going by a company that needs the conflict to continue. The moment the Doctor works out that nobody has actually seen the other side is the best single beat in the series. The ambulances are the nastiest touch of all. They arrive when you’re wounded, work out whether treating you is economical, and kill you when it isn’t, all while a calm synthetic voice offers reassurance, and I could picture exactly which meeting approved them.
Gatwa is extraordinary in this
Given nothing to do but stand and talk, Gatwa turns in the performance that proves the casting. He’s frightened, he’s furious about being frightened, and he keeps having to stop being either in order to think. He switches between those three constantly and none of it looks like acting. The scene where he talks a dying man’s daughter through what’s happened to her father is the best thing in the run so far, and it works because Gatwa plays the Doctor’s kindness as an effort instead of a default. He’s being gentle while standing on a bomb, and I could see what it cost him.
The supporting cast is small and used precisely. Canterbury is a young soldier who has never questioned any of it, Mundy Flynn is competent and out of her depth, and Splice is a child who has to be told her father is gone. None of them get much screen time and all three land, because each is given exactly one thing to want. That economy is what an episode with a stationary lead needs. It’s the kind of discipline the rest of this run keeps skipping in favour of another location.
Ruby gets something to do at last
Millie Gibson is finally handed material with weight. Ruby is the one who has to move, fetch, improvise and eventually get shot, and the stretch where she’s in danger while the Doctor can’t take a single step toward her is the tensest of the series. The episode is smart about their dynamic, too. He’s the one who can’t act, so she has to, and the reversal shows how much of the usual Doctor-and-companion rhythm depends on him being mobile. Give the companion the legs and the Doctor the words and you get a genuinely different two-hander.
The ambulances and the algorithmic cruelty rhyme with things this show has done before, and I noticed the echoes without minding them. Underneath, this is closest to Midnight: confine the Doctor, strip his advantages, and see what he’s actually made of. Midnight did it with a room full of frightened people, and this does it with one small metal disc. Both work because the rule never bends.
An argument that is the plot
The soldiers are the Anglican Marines, a fighting order who have been sold a war as a religious duty, and the episode has a lot of quiet contempt for the arrangement. That contempt isn’t for the men, who are decent and frightened, but for the machinery that recruited them. The Doctor doesn’t deliver a speech about organised religion. He just keeps asking practical questions the soldiers can’t answer, and the gap between what they’ve been told and what they can check does the work. When he asks how long it’s been since anyone saw the enemy, and gets a look instead of a number, the whole thing comes apart without anyone making a case.
That’s the difference between this and the political aside in Space Babies, which stated a position and moved on. Here the argument is the plot. You can’t separate the idea from the mechanism, because the mechanism is a company selling weapons to people it has convinced are fighting somebody. The resolution leans on the system being talked down through the dead man’s recorded personality and his daughter’s voice, which is emotionally satisfying and mechanically a bit soft after fifty minutes of hard rules. I don’t mind much, because the ninety seconds before it, where the Doctor works out what’s about to happen and there’s nothing he can do, more than pay for it.
Rating: 4.5/5. Loved this. It’s furious, frightening and tightly built, and it finally gives Gatwa a script worth his performance. The war-as-business-model idea is the sharpest thing this show has said in years, Ruby is properly used for the first time, and the whole thing rests on one immovable rule that never gets fudged. Only the slightly soft ending keeps it off a five.