I haven't seen Jekyll, no - but it is one of the things on my list (which i will get to eventually! I'm also watching Fringe for the first time, just approaching the end of season 2).

And a big *facepalm* from me because this entire time i had been thinking "the spaceman is coming to eat me" was all about the astronaut suit, and it had never ever occurred to me that it was the Doctor. But as Owlie said below it can't be because for her to have been calling the Whitehouse she must already have been inside it. Then that shot that we get of her in her nightdress, hiding behind the wall, looking petrified despite having asked for help. Suddenly it all slots into place.