Car after explosion

Creepy incident occurred with one driver. In the car was a balloon with acetylene, but the valve was not closed properly. During the night the car interior is completely filled with gas. Owner of the car smelled gas and decided to roll the car out of the garage to the street. Rolling his car out of the garage, he pressed the window to ventilate the interior.
At this point, and there was an explosion. By happy coincidence, the driver escaped with only a fragmentation head injury, but completely deaf in his right ear.