Board Thread:Inclusion debates/@comment-2.26.183.189-20170416191252/@comment-1789834-20170419032208

I can answer two points raised here from that interview with Moff. Firstly, OS25 states that it wasn't intended as to fit into The Pilot. That's not entirely true. According to Moffat, when asked by Crystal if it was always intended to be there, he said that he wasn't sure. If he could fit it in, he would, otherwise he'd scrap it. As a fellow Doctor Who nitpicker, Moffat tried his utmost to make it work.

The second point is what CoT is saying about guarding the Vault. And it's a perfectly reasonable back-up to the Doctor's comment about "returning to 2017". The Moff explains that the Vault, which is this series' arc, is vitally important. The Doctor has to guard it with his life and never to leave for a second. He goes on to ask "why would you ask the most irresponsible man in the universe to guard the most important vault?". So, yes, I agree with CoT. It's most plausible here that the Doctor is remembering that he's "promised" (as was stated in the episode) someone that he'd stay at St. Luke's and guard that vault. And thus, he feels the need to return at once.

That's my take and none of this is really my opinion. It's taken from the interview and also it's just putting the two sources together and coming up with the most logical answer.