Everywhere, walls come down, sealing them all inside the hospital, and still the Doctor shouts to go further in; still the zombies press in toward them. The door to Intensive Care opens, and the zombies reach out into the hospital, infecting people as they scream. Cassandra, Chip, and the Doctor finally reach the cellar, but can't use the elevators because of the quarantine. They get separated from Chip; the Doctor tries to go back -- "someone will touch him!" -- but Cassandra tells the Doctor to leave him, since he's "just a clone thing" with "only a half life" anyway. Chip calls pathetically after them, but the Doctor has to follow Cassandra -- her body is his responsibility. "I'm sorry, I can't let her escape!" he calls. Terrified, Chip calls after them once more and then runs, still safe for the moment.
Clovis emerges into the corridor and acts like an asshole for a second before she sees the zombies lurching out of Intensive Care; she screams and presses an alarm button, and then goes running in the opposite direction. The Doctor and Cassandra rush back into the room where Cassandra took over Rose's body. Cassandra tries another door, but it's got a zombie problem too. She screams and whines and the Doctor tells her, angrily, that the first order of business is getting her out of Rose's body: "That psychograft is banned on every civilized planet! You're compressing Rose to death." She whines that her original skin is dead, and the Doctor tells her it's not his problem: "You can float as atoms in the air." He points his screwdriver at her and demands that she give Rose back. Cassandra shrugs, and leaps from Rose's body into the Doctor's. This causes the Doctor to act like Snagglepuss for some reason. Cassandra investigates her new body at length, and it's less funny, but kind of scary and wild, and she laughs at Rose for thinking the Doctor's "a little bit foxy" -- "You've thought so too, I've been inside your head..." -- and Rose blushes a bit. "You've been looking...you like it!" David Tennant is very adorable in lots of situations and he can be very scary when he is full of rage, but there's nothing quite so off-putting or unarousing as David Tennant pretending to be possessed by Madame Hooch; it's like a Perfect Storm of scary. The zombies crash and get scarier and Cassandra's useless. Rose grabs a ladder and decides thatthey've gotta go up, now. Doctor Who and all the running around. Cassandra shoves Rose out of the way and starts up the ladder; Rose follows after.