When Nixon is telling the NASA security men to let the Doctor go he tell them, "I am your Commander-in-Chief." The President is the Commander-in-Chief of the United States Armed Forces, but not any civilian organizations. NASA does some work for the military but is completely civilian and separate from the military. See more
[to the Silence, who are holding Amy hostage
Oh, hello. Sorry, you're in the middle of something. Just had to say, though, have you seen what's on the telly? Hello, Amy, you all right? Want to watch some television? Ah, no, stay where you are. 'Cause, look at me, I'm confident. You want to watch that, me when I'm confident. Oh, and this is my friend River. Nice hair, clever, has her own gun, and unlike me, she really doesn't mind shooting people. I shouldn't like that. Kind of do a bit.