Cybermats were released by the ship's computer and began attacking the crew and infecting them with a nanovirus which would result in their cyber-conversion. He escaped on vehicle, but crashed in a cave, where the Eleventh Doctor and Amy had just arrived. The Doctor saved him by warming up some water with his sonic screwdriver and giving it to him to prevent hypothermia. Thanks to the Doctor finding an alternate path back up to the TARDIS (due to a sprained ankle), Chisholm explained what happened and much to his shock (after seeing the inside of the TARDIS), he found that they had taken him back to the base. There, he was attacked by a Cybermat and bitten; he locked himself in a tower to prevent himself from hurting Amy and the Doctor when he changed. Though they didn't listen to him, Chi