Steven Moffat's return to Doctor Who had left me very excited to watch this episode. He easily produced the best stories of the original Russell T Davies era, and his era as showrunner was also excellent. Boom is the first time in over a decade that Russell T Davies and Steven Moffat have both collaborated within the same era, and the resulting episode really doesn't disappoint.

As the promotional material suggested, Boom really is an excellent Hithcockian tale. The Doctor spends the entire episode stuck on a landmine, and it makes for such a tense watch. The episode brilliantly builds up a sense that the landmine could go off at any moment, and Ncuti Gatwa's performance really elevates the sense of peril.

This is easily Ncuti Gatwa's best portrayal of the Doctor to date. His delivery of Moffat's poetic lines is sublime, as you really feel the sense of the Time Lord's power and authority as he rails against the militaristic system. This Doctor also feels incredibly vulnerable here too as in the previous episodes, reduced to tears whilst stuck on the landmine.

Varada Sethu's appearance is a nice bonus. She does a superb job as Mundy, seeming tough but also caring. It doesn't seem as though Mundy is who she will be playing when she's the companion, which is a shame, as Mundy would make for a great assistant to the Doctor. Speaking of companions, Ruby Sunday getting taken out in the episode was certainly a surprise. Having Ruby seemingly die coupled with the return of the snow was an extremely effective means of raising the tension, and again contributing to the looming sense of danger in Boom. If Ruby isn't safe, then what hope is there for anyone else?

I have a feeling Susan Twist as Ambulance will have put a spanner in the works for a few Susan Twist theories. It's hard to see how she can still be Susan or the Meddling Monk, when the Doctor sees her in this episode, and she's a rogue AI medical machine. Although I suppose it would be a little in character for AI to steal somebody else's likeness, and also for the Doctor not to recognize another Time Lord. I loved the reveal that there was no enemy, though, and that the computer was creating fatalities by killing the injured to make it look as though a war was being fought. An extremely clever Moffatism.

Overall, this episode would be a solid 9/10 for me. A typical Moffat masterpiece, with some shocking twists and scathing political commentary on militarisation and AI. Unfortunately, it doesn't quite land the conclusion, which feels a little too convenient, but despite the ending, this is a Steven Moffat episode that creates a big bang rather than a whimper.