So, the short of it is Pam the Demented Jeep took an unfortunate accident involving a deer on the road and made it into an anti hunting thing because there was a shotgun that was apparently left loaded and unlocked in the back of the hunter's truck. (even though Pam doesn't say it was a truck, I'm going to assume it was - foolish to strap a deer to the top of a Prius) And somehow, the gun went off, shot through the back of the bed, the back of the cab, and the seat, to lodge a bullet into the drivers leg.
Let's assume this is 100% true;
A ) The gun discharged after the deer ended up in the road. has nothing to do with the accident itself.
B ) The gun would have discharged after the vehicle rolled. It isn't responsible for the accident.
C ) The driver ended up shot after the vehicle rolled, meaning that his passenger would have still been injured, and in the coma he is in now.