Doctor: "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."
River: "Thank you, sweetie!"
Doctor: "I know you're team players, and everything, but she'll definitely kill at least the first three of you."
River: "Well, the first seven, easily."
Doctor: "Seven, really?"
River: "Oh, eight for you, honey!"
Doctor: "Stop it."
River: "Make me!"
Doctor: "Yeah? Well maybe I will!"
Finally Amy's like, "STOP FLIRTING AND GET ME OUT OF THIS CHAIR."
So while Rory fusses over her, the Doctor explains that they will now be offering unconditional surrender, based on the shit he's about to pull. He says he'll let them go free, but then it turns out that was a lie, because one thing about Eleven is that he doesn't mind shooting or guns or killing or prejudice or murder or any of the things the Doctor's always disliked. Just one more improvement, in this iteration: The Doctor's twinkly bloodlust.
He bugs them about the little girl, for like one second, but then lets it drop -- she's a small mystery, as far as he's concerned; the rest know better and can't tell him -- so he can explain the plan. Millions of people on Earth, spreading out through the galaxy over the next billions of years, all of them remembering our first steps on the moon. And in the gap between "one small step for man" and "one giant step for mankind" is a gap where the Doctor and Canton insert the video of the injured Silent saying, "You should kill us all on sight, you should kill us all on sight," which nobody will ever remember seeing, until the moment they see another Silence, and then kill it, and then go back to forgetting.
Which is pretty neat, in the exact same meta way that in "Blink" we never saw the statues move. Moffat likes it when the thing could be real; we like that too. Black-cat hiccups in the Matrix, every statue possibly alive. Except for how, in this case, it's a post-hypnotic suggestion he's giving the entire human race to commit genocide whenever possible for the rest of time.
Hey, remember when even the Doctor felt a little bad for Sister Mine?
Yeah, that show is over. That's not the show you're watching anymore. I still haven't figured out why just saying that pisses people off so much, but it goes to/comes from a particularly recognizable, weirdly emotional, irrationally projecting, overinvested place that has come up exactly twice in my career on this site, other than with this show: The crappy BSG finale, and Taylor Hicks fans. A very particular, very embarrassing kind of defensive, personal nastiness that, more often than you'd think, is often followed a few days later with unsolicited apology: "I'm not sorry I acted like such a crazy asshole, but I think it had something to do with needing a stranger on the internet to like the same things I do."