This man had pulled into the driveway of his house.
The driveway had an incline and it would take more force for his truck to roll on its own while pulling in the driveway.
He was on the phone distracted and thought that he had put the car in park mode since it wasn't moving.
He got out and was typing in the garage code when the truck slid down and ran into him, squishing him against the garage door until he squeezed himself out.