Think this fan-made video sums it up pretty well :(

@TheCrowbar said:

SPOILER WARNING: Click here to reveal hidden content.

Are they stuck in that hotel forever? Where did they get sent to?

@Mercy_: It never sunk into me the hell the Doctor goes through being nigh immortal until this episode especially

@TheCrowbar: It first hit me in series 6 (?) with first the giant space whale and then there was the episode with the minotaur and you see all the parallels.

@Mercy_: I don't know the franchise well enough, but I can't help but think the whole

@TheCrowbar: It's not so much that he would go evil, just that he starts losing perspective on his humanity so to speak. Have you been keeping up with the whole season? It's touched upon in the Mercy episode. He starts losing sight of what decisions are the better ones as opposed to the most pragmatic and Amy makes a comment about how he's been travelling alone for too long. The Companions ground him, allow him some humanity and allow him to be a bit more than just what he is. He destroyed the entire Dalek race, that's not something that sits easy on a person and it speaks to his underlying trait of doing what's better for all as opposed to what's better for the few, or for himself.

@Mercy_: Yeah, I'm still trying to catch up. I'm hoping it'll give me that fix Torchwood used to.