Just thought I would point out that there are two space suits, and the doctor even tried one of them on.

My bet he is in the suit when it walks onto the shore line

What do you think?

Yeah, my money's on the Doc'. He kills himself to create a paradox that if he's dead he wouldn't be alive to kill himself. It's cheating of course and shouldn't be possible (even within a the fictional concept of time travel) - but that's never stopped Moffat before, eh!