Something similar happened to a guy at work. He was blowing dust off himself with an air hose and put it down his pants. He turned the nozzle toward himself and blew up his abdomen with air. He wasn't seriously hurt but had to go to the hospital to get the air out.
I can see how this can happen. People don't realize how powerful compressed air is. They routinely work with it. They hear "50 pounds per sq.inch" or something like that our machinery can easily create and don't realize they can be literally torn apart by that. People need to take a pressure gauge and see how much pressure they can produce. It takes huge amounts of energy to create 50# compression of a significant volume of air - but that is so common place for us that it isn't respected much.
Our incredible technology is not respected and this type of thing gets played out in many ways.