This may be old news but I just caught it while re watching this episode. In the restaurant ( the first one) when sherlock jumps back into John's life Mary says, " But you're dead".
To which sherlock replies "No,".
Mary then says, " You jumped off a roof"
Sherlock again replies "No."
So .... Didn't leap off the roof at all ? Or just trying to hush her up so he can get back to dealing with John ?
I guess it doesn't really matter but I found it interesting that I never noticed it before and was curious if anyone had any thoughts about it.