Henson and Rodriguez make it to the extraction vehicle. There, they prepare to rescue Alex and Ellis, but Rodriguez is bitten by a zombie who was locked in the back of the van by the soldier assigned to guard it. Henson executes Rodriguez, and the duo arrive in front of the science building as Alex and Ellis fight their way through a horde of zombies. Alex and Ellis are saved by Henson, but the blood sample vial is destroyed in the process. They are forced to turn back, with ten minutes before the military releases the missile level the campus, and fight their way back to the confinement room. They retrieve a second vial, but Henson is bitten on the ankle. She remains behind and commits suicide, as Alex and Ellis escape before the missile strikes the campus. Only Ellis makes it out before the missile hits, with Alex surrounded by zombies. Bart breaks free from the dormitory by amputating his hand and forces Ellis to hand over the vial. Bart decides to kill Ellis anyway, but Alex is revealed to have survived and kills Bart. His dying action is to pull the pin on a hand grenade, destroying the vial in the process. Alex is wounded but uncertain of whether she's infected. Ellis refuses to execute her, and the two leave together as they head to Seattle, finding that the infection has spread to the rest of the city.