I hope you don’t mind that I answered publicly. After emitting this wall of text I wanted to share it to see what other people think.
Well, I’ve got troubles predicting this stuff. First, I really was waiting for the “aha gotcha” moment in this one, where what was obviously going to happen happened. The moment tattoo-swapping was introduced, I knew Clara was going to take a tattoo away from somebody. I was thinking very briefly that the Doctor would get one for disturbing the peace (that being a thing he does well), but simple tight plot means there was only one. When Clara took Rigsy’s I thought “okay, typical hero of a tragedy, undone by her own flaws and her hubris in thinking she can survive this as she has all the others”. But that was too obviously a straight line through the plot! I was genuinely surprised when it actually worked out directly that way.
There is a lot of energy in the oncoming doom plot, which the characters can see coming and attempt to thwart in vain, but this story wasn’t that plot. The oncoming storm stories when they work are just brutal experiences, because you watch characters struggle in what you know is going to be a pointless fight and ouch. That was the last few minutes of this episode, but not the bulk of it.
Next point I’m thinking about: this is the inciting incident section of a three-parter. The second one will complicate matters, raise the stakes, and with a revelation/reversal, show us who the real antagonist is. The stakes are probably the Doctor’s moral compass, not his life, because Who is always more interesting when it’s about his moral choices. Third episode (season finale) will be final confrontation, resolution, denouement (probably the diner).
My current theory is that the twist comes next, probably at the end of “Heaven Sent”. Something we learn will upend what we just saw, somehow. Who kidnapped the Doctor? Why? Why are they shoving him into a castle of terror™?
There are a number of plot-hole-like questions I have. The Doctor, when unleashed, can do anything. He told us as much in “The Girl Who Died”. He can restore life to Ashildr using a hacked medkit made by another species. Why can’t he bring Clara back to life? Why didn’t he even try? There are ways he can react to death that aren’t destruction. Why not here? Why did he leave Clara’s body in the street? He is unsentimental in some ways, but I’d expect him to do something sentimental here or at least try to revive her. How does the quantum shade thing work? Does he know things about it we don’t? Why? Do souls even exist in the Whoniverse?
I’m seeking Watsonian explanations here not Doylist ones, if that makes sense. Answers within the reality of the show.