Then the Spaceman comes walking in, causing her to flip out, and the faceplate comes up to once again reveal the little girl Jefferson. "Just tell me who you are! I'm sorry, I didn't mean to shoot you. I'm glad I missed." (Cliffhanger resolution! She ... missed.) "But you killed the Doctor, or you're going to kill him..." The little girl is not so forthcoming -- and even though Amy blew a hole in the faceplate, she's still doing the vacuum-breathing thing for some reason -- with details, but just keeps begging (in an American accent, note) for Amy to help her. Staring, staring, and then two Silence appear flanking the Spacegirl, and Amy shrieks (because sure) and the door slams shut on them, locking us out.
Downstairs, Canton is still doing unspecified filing of paperwork (not knowing that Amy has solved/unsolved the case upstairs) and there's a scary knock at the door. Renfield goes to the door and has a hushed meeting with them, about which he refuses to tell Canton because he doesn't remember what just happened. Canton strides to the door, which opens of its own accord, so he clicks his palmcorder and asks the Silent to tell him what's going on so they can remember it later.
While Amy screams for help upstairs, the Silent goes, "This world is ours. We've ruled it since the wheel and the fire. We have no need of weapons." Canton shoots him, because he's American and that's what we do. Ha-ha! Americans shoot things.
You know what else? Nixon was paranoid and recorded everything, which was his downfall. I appreciate the concept of history being rewritten thanks to the Doctor -- it's kinda what the show's about -- and there's a certain small bit of elegance in having it happen here, when the paranoia is justified because of the Silence and when the recording thing is already established, but you know what would have been more elegant? Having the joke be something more than the Doctor literally saying, "You have to tape everything that happens in this office, every word, or you won't know if you're under the influence! You have to trust me and nobody else!" Because get it? Do you?
Also, when Nixon asks why he was fucking around with Apollo XI, the Doctor totally goes, "Think. Try to think." Like you're an idiot if you don't immediately grasp that the Doctor's going to kidnap an injured Silent and get it to say certain words in the correct order and then insert a subliminal command into the moon landing to cause a worldwide genocidal revolution that nobody will ever remember. Like duh, Dick!