I actually didn’t mind Death in Heaven that much but one thing I hated was this

I really didn’t care that she was throwing the keys away. I wasn’t afraid for the Doctor because of this

Moffat himself wrote out the need for a key to open the TARDIS. It even works for Clara, which Moffat also wrote

So this all seemed like an empty threat. Sure you can explain it away by saying something like the doors have to be unlocked for the snapping to work in the first place but that’s never explained. I assume the snapping works at any time. I might be nit picking but I don’t care. It was annoying and ruined the emotional impact of the scene for me.

Remember Series 7, Episode 7 The Rings of Akhaten where the Doctor was giving his speech and he said, “ …I saw the birth of the universe and watched as time ran out, moment by moment, until nothing remained. No time, no space. Just me! I walked in universes where the laws of physics were devised by the mind of a madman!…” I have kind of a crazy unrealistic theory that in Episode 4 of Series 8, Listen, that the “thing” looking for the last companion, alone on the very last planet of the universe, the “thing” knocking on the door wanting to be let in was The Doctor.