his heat signature in his quarters. He leaves the lab again and spies on Linda and Matt, becoming enraged when he sees them about to have sex. Becoming increasingly unstable, Sebastian later kills a dog being used as a lab animal in a fit of rage. The team discovers they have been watching a recording, and Sebastian has been leaving the lab without their knowledge. Linda and Matt go to Kramer's house and confess their experiments. After they leave, Kramer attempts to alert the Army. Having followed Linda and Matt to the house, Sebastian cuts off Kramer's phone connection, then drowns him in his swimming pool. The next day, Sebastian waits until the whole team is inside the lab before he disables the phones and elevator codes except for his own. The rest of the team congregates and decides to hunt Sebastian down and subdue him. At the same time, he begins to murder the team members one by one, with Janice being his first victim after falling behind the others. Linda and the others hide in the lab, while Matt and Carter take tranquilizer guns to hunt for Sebastian using thermography goggles. Sebastian mortally wounds Carter before getting into a fight with Matt. Linda saves Matt. Sebastian then kills Sarah and Frank, and locks an injured Matt and Linda in the freezer, leaving them to die. Linda constructs an electromagnet using a defibrillator to open the door, then gathers materials to assemble a flamethrower. Meanwhile, Sebastian builds a makeshift bomb that will destroy the facility after he leaves using explosive chemicals and a centrifuge; he destroys the keyboard so that nobody can stop the machine. Just as Sebastian enters the elevator, Linda fires the flamethrower at him. Sebastian escapes and the two fight. Before Sebastian can kill Linda, Matt strikes him with a crowbar. Sebastian recovers and approaches Matt and Linda from behind with the crowbar, but Matt deflects the blow, throwing Sebastian into a nearby circuit box, shocking him and rendering him partially visible. Linda and Matt find the bomb, but cannot stop it. They attempt to climb a ladder in the elevator shaft to escape as the bomb explodes. Despite his injuries, Sebastian grabs Linda's ankle. He pulls her off the ladder and onto the top of the elevator. Linda disconnects the elevator cables, causing the partially visible Sebastian to fall to his death down the shaft.