Other mistake: When the Jeep crashes and John gets out, he sits on the ground behind the vehicle and picks up a shard of glass that's supposed to be from the vehicle accident. Given that all the glass on the jeep shows to be intact, the glass couldn't have come from the Jeep as insinuated by the audio and placement of the shard.
Suggested correction: The windshield broke when the Jeep crashed into the tree and the driver was thrown through it. So the glass of the Jeep is not all intact. That being said, the shard John picked up was a long way away from where the windshield broke.