Look, Doctor Who isn't a movie, despite David Yates' best hopes.
It's anthology television, a jukebox of genres and adventures linked only by the same character turning up in a blue box.
(Unless he's been sent back in time by statues, or killed off in an alternate timeline or something like that. The show's got range.)
This is, of course, why Doctor Who is the best show ever. It's not the one episode, it's the breadth of what each episode…