Once you see spoilers, you have 66 seconds to live.
Well, after last week's excursion into bad science, the series is back on track (oh, ho, ho) with nothing less than a classic Universal Horror monster on a train flying through space. I'm going to jump right in, because the script does the science a great service in this episode. Little throwaway lines here and there to explain things. How does a train fly through space? Well, as the Doctor mentioned, it's a little bit wider, which could easily account for propulsion, atmospheric systems, insulation, and other various and sundry things that would be required for safe space-flight. The mummy's tech is fairly well-established in science fiction as well, and was in fact handled better here than even on the venerated Star Trek: The Next Generation.
If you'll cast your mind back some decades now (yikes, it has been a while), Star Trek: The Next Generation had an episode called "The Next Phase". In this episode, the Enterprise comes across a crippled Romulan ship that had been experimenting with a phase-cloak. Geordi and Ro Laren beam back after attempting to assist, but are lost mid-transport. Turns out they're knocked out of phase with the Enterprise, and spend the rest of the episode being chased around the ship by an angry phased Romulan. They can run through walls, but don't fall through floors. Any oxygen transported into phase with them would have long since been exhausted. Never mind how the angry phased Romulan is taken out by being pushed through a bulkhead into space.
But here, the mummy is initiating a phase transport that's only slightly out of phase, say somewhere between the dimensional phase its using and the one we're in, so that the victim is still visible and (maybe) tangible, explaining the victim's blurry vision. The victim is only alive for 66 seconds after being taken out of phase, so hardly time to use up any phased oxygen and suffocate. The mummy doesn't need to worry about oxygen, as it's life-support tech is already fully capable of keeping dead and rotting flesh mobile and animated, and it's clearly completely out of phase, made obvious by the shiveringly gruesome sight of its hand reaching right through the Doctor's head. All in all, this is some refreshingly solid science fiction premise, especially after Kill the Moon's giant space butterfly hatching from the moon and laying a new moon immediately after birth.
That woman's name is Foxes, and she's appearing courtesy the BBC
Story-wise, I like where this episode is going, too. It's setting up some real character conflict for Clara, who (BTW, can she rock a flapper's gear or what? A far cry from her normally conservative wardrobe) has been experiencing more character growth in half a season than past companions have in 2 year's time. She clearly has an addictive personality and, despite her anger with the Doctor's actions previously, she can't bring herself to quit him. To quit her adventures. Even after she realizes that this wasn't just a peaceful “final trip” she gets mad for a moment, then outright lies to him about her and Danny's discussion before eagerly begging for another hit.
And I can't help but feel that, had he not had that row with Danny a few episodes back, The Doctor might well not have made it out of this one alive. When he realizes that the mummy is a soldier, it marks the first time he treats a soldier with respect in this series. Surrendering, then relieving him of his duties. And finally, the touching moment at the end when he comes clean. He's a man who makes hard decisions, and has to live with the memories of those hard decisions. Which is why he so rarely looks back, because if he did, he'd see so much regret and pain that he may not ever look forward again. Capaldi really carried this scene, proving himself adept at handling the quiet moments as well as the manic, shouty ones we've grown quickly to love him for.
Please tell me I'm not the only one that caught the First Doctor's tie, the Jelly Babies in the cigarette case, and the “Are you my mummy?”
Next week: I swear, I have that tiny TARDIS sitting on my shelf.