Captain Jack hops down onto the rails near where Algy is pacing: "Hey, tiger! How's it hanging?" But when Algy turns around, you can already tell: "Mummy?" Jack -- too big, too much -- won't buy it: "Algy, old sport, it's me. It's me, Captain Jack." His smile fades, as he looks on at Algy's confusion and curiosity: "Captain Jack? Are you my...mummy?" Algy begins to cough and falls to his knees, and then begins to change. I wish we'd seen more about Algy, his pluses and minuses, because I think that Jack's feeling something here -- that it's becoming real, but we can't bear witness to that because all we've seen is him getting his ass slapped and then being mean to a dirty young homeless woman. In front of Captain Jack, Rose, and the Doctor, Algy stops being Algy. The Doctor and Jack order the other soldiers to stay away from Algy, and the Doctor murmurs that the effect has become airborne, and that it's accelerating. "What's keeping us safe?" asks Rose. "Nothing" is the Doctor's reply. So of course the air-raid siren sounds at this point, and Rose remembers that the bomb is due to hit exactly where they are. Captain Jack nods, and somewhere Nancy begins to sing. "Never mind about that," says the Doctor. "If the contaminant's airborne now, there's hours left." For what? "'Til nothing," the Doctor says. "To forever. For the entire human race. And can anyone else hear singing?"
Nancy sings "Rock-A-Bye Baby" to Jenkins, whose gas-masked head is on the table. The door creaks open, and Nancy and the Doctor communicate silently: he, that she should continue to sing and care for the kid; she, that she's handcuffed in there. Girl, I feel you. She keeps singing, and the Doctor sonics her cuffs, as Rose and Jack watch from the door. Soon enough, they take off from the shed, leaving Jenkins fast asleep.
Back at the bomb site, the Doctor and Captain Jack uncover the tarped transport, as Nancy and Rose look on. "You see? Just an ambulance," says Jack. Rose tries to explain to Nancy how it's an ambulance from another world, as Jack's discovering that Algy's men have been trying to get inside it. "Of course they have," says the Doctor, in his "you stupid apes" voice. "They think they've got their hands on Hitler's latest secret weapon. What're you doing?" Jack says he wants to open the thing up so that Algy's men will see that it's empty. His need to prove...that says more to me about the Doctor than it does about Jack. Jack fucked up and wants to clear his name, but it's not like anybody in London is going to talk. But you meet the Doctor, and then you redeem yourself. Those are the rules. The keyboard on the ship's lock pops with sparks, and they fall back. The Doctor realizes that it's emergency protocol, now that the ship's actually crashed onto a planet. A red light on the control panel blinks at them.