Bracewell argues with them, that he created them out of his own genius, and they demonstrate quite graphically that he is wrong: A laser to the hand reveals his own alien technology inner workings. He is their android, sent to bring them into existence so that they could maneuver the Doctor into saying this one specific thing. Dicey, contingent, but makes sense in the larger emotional-philosophical context. But unless you're not getting it, let's spend awhile making it explicit. "I wanted to know what they wanted, what their plan was. I was their plan!"
"Commencing Phase Two. The Progenitor is activated! It begins! Testimony accepted!" They tell him not to beat himself up for falling into their trap, but he's weirded out. And do they chase them now, Amy wants to know? Is that what we do now? No, he says, it's what he does now. "I've got to stay safe... Down here? In the middle of the London Blitz?" and he nods, rubber-faced: "Safe as it gets, around me."
Left alone, Churchill is droll in explaining what they do now: "KBO, of course." Keep buggering on! They stare around for a bit, and then somebody notices a UFO in the sky. Amy knows he's up there, "right in the middle of everything," but can't figure out how that helps to know. Up on the roof, the watchmen yells about the Blackout, so we'll remember it for later.
The TARDIS jumps onto the ship, and he says hello and asks for tea; they rush to Exterminate but he says he's got the old girl set to self-destruct. When in doubt, like Winston far below, sacrifice the angels first. (Although, as we'll learn later, it's not actually a self-destruct: It's a cookie meant for tea. Cute, cute in the same way as Ten being brought back to himself by a cuppa.) He looks around, noting how trashed and tired things look up there, and reminds us -- sort of -- how we last left the Daleks. I can't even remember, really. There was the God one, that was Rose, and then there was the time with the... No, that was the Toclafane. After the God one, there was that ridiculous story where they evolved into the things with cat-penises on their head, right? Good Lord. Effing Tallulah and the genetic spirit of humanity and whatever.