"How the heck did that happen?" Injuries

I was helping a fellow mechanic back a fire truck into the shop. He was out of sorts and stopped to readjust. I jumped up next to the truck to move some parts that were about to hit the truck at the same time he started moving. I got caught between the truck and the wall. Stupid move on my part. I earned myself 5 broken ribs on the left side of my back and a trip to the ER.