SpoilersI think the idea was to transfer his head to different bodies till they were able to bring a cure to his body. At least thats what it seemed like. I was confused until scully found that shit about the dogs having their heads cut off and than transfered to a new body and living for two weeks. I was under the impression that the guy had a rare blood type and they were harvesting parts to keep him alive until they could fully cure him.
I didn't really find huge plot holes. Or a real problem with the storyline. I just thought it lacked the suspense it deserved. I would rate the film 2.5 out 5 stars. A mediocre film because I did enjoy aspects of it.
And the door thing..it could have been locked so the dude punches it in and than leaves it open to make it look like she walked away. One could assume the glass was broken somehow during the wreck.