Nancy calls Rose to the perimeter, scared. The masks are getting closer, shambling over the rails of the traintracks. Rose comes running back, asking whether the ship is somehow summoning them. "It's calling up the troops. Standard protocol," the Doctor replies. But they're not troops, just Londoners in the Blitz. Just people. "This is a battlefield ambulance. The nanogenes don't just fix you up; they get you ready for the front line. Equip you, program you." Rose realizes that this is why Jamie can do all that stuff with the radios and the telekinesis. The Doctor: "...A fully equipped Chula warrior, yes. All that weapons tech in the hands of a hysterical four-year-old, looking for his mummy. And now there's an army of them." Weapons of mass reconstruction. They crowd the fence, and Jack asks why they aren't attacking -- they're waiting for the child? Nancy corrects him: "Jamie. Not 'the child.' Jamie." The Doctor looks at her and wonders.

Rose asks how long it will be until the bomb falls on them, and Jack says that it'll be any second. He's none too comfortable. "What's the matter, Captain? Bit close to the volcano for you?" asks the Doctor -- disgusted, as usual. "He's just a little boy," says Nancy, getting upset. Doing double duty here. Nancy adds, "He's just a little boy who wants his mummy." The Doctor acknowledges that: "There isn't a little boy born who wouldn't tear the world apart to save his mummy. And this little boy can." Rose yells about what they're supposed to do, and the Doctor admits that he's at a loss. Nancy starts to cry: "It's my fault." The Doctor tries to comfort her, but she grows insistent. "How can it be your --" Without finishing his sentence, the Doctor goes from gentle to intense all at once, staring out at the masks, still calling for Mummy, and then to Nancy, who's sobbing crazily. "Nancy, what age are you? Twenty? Twenty-one? Older than you look, yes?" A bomb nearby drops as she nods, and Rose and Jack get very iffy: "Doctor, that bomb. We've got seconds," says Captain Jack. Rose asks whether Captain Jack can't just teleport them out, and he apologizes that, with navcom back on, it would take too long to override the security again. "So it's Volcano Day," says the Doctor, without looking up from Nancy's face. "Do what you've got to do." Rose stares -- "Captain Jack?" -- betrayal on her face, but Jack just looks at her, and disappears. Who's he going to be?