What?
Possessed Jonesy is shot and dying. Why does Hobbs kill himself? Just leave. Because he's dumb he seemed to expect the demon to turn up on his own and in the form of a stranger. Regardless, just shoot him in the belly, tie him up, hop in the car, home in time for tea and crumpets. By the time the host body bleeds to death Hobbs is out of range. There are endless variations to that approach that cater to almost any scenario. That's just one of a torrent of things that don't make sense.