Susan surmises that the Judas breed's accelerated metabolism has allowed them to reproduce at a similarly accelerated rate, and have managed to evolve over tens of thousands of generations within only three years, including developing the ability to mimic their human prey. The group formulates a plan to get the car moving: Peter will switch the power on, and Manny will switch the tracks. Susan projects that the Judas will spread throughout the tunnels and overrun the city unless they are able to kill the colony's single fertile male. Manny finds Chuy but is killed by the male Judas, so Susan goes in search of him but finds only Chuy. Leonard's injured leg starts bleeding heavily, so he creates a diversion that allows the others to get away, before being killed. Peter finds a dumbwaiter and puts Susan and Chuy in it, but stays behind to destroy the breed for good. He is chased into a room where hundreds are nesting, and blows them all up by setting fire to a loose gas pipe, before diving underwater to safety.