I don’t think I had seen this episode more than once. It left a bad taste in my mouth originally. I actually like this more than I expected. I don’t love the concept of it, but I really do like the guest cast and how the characters interact. Surprisingly, I even like David Walliams.
So this is apparently the end of companions living on the TARDIS with the Doctor for the remainder of Moffat’s time as showrunner. I really don’t know why and I really don’t like this concept of the Doctor popping and in and out of his companions’ lives. The Doctor travels with someone and doesn’t come back. I think that’s a core part of his character.