He was later tested by Kate, a test that he passed because he had metal fillings.The later on he and Lars were tasked to bring in Carter and Derek in from the shed. When the two discovered that Carter and Derek were no longer inside of the shed, Jonas suggested that, he and Lars should go back to Kate and the others. Though Lars decided to look for the two prisoners. When Lars disappears, Jonas flees back to Kate and the others. When the others run to try and stop Carter and Derek, Peder prepares to burn the two, but is shot in the head, killing him instantly. When Edvard goes to check on Peder, Jonas notices that the flamethrower is about to explode. When Edvard is knocked out from the explosion, Sam orders Jonas and Colin to pick up Edvard, while they are carrying him one of Edvard's hands breaks off and begins to assault a horrified Jonas. After the Edvard-Thing assimilates Adam and escapes the room, Kate sees Jonas in the process of being assimilated by the creature as it forces it's way into his mouth along with a large portion of his right hand merged with the Thing from his struggle with it. Jonas then gives Kate a pleading look, she puts him out of his misery and incinerates him.
- Jonas' death scene was similar to that of Windows' in that both men (after being hopelessly mauled by an imitation) were torched in mid-transformation; while leaning up against a bookshelf of board games in the rec room.
- Jonas assimilation via tentacles penetrating and merging with his face was also a reference to Garry's fate in the original Carpenter's film.