When I was in high school, we had a 1-ton flatbed truck parked behind the lift, which had a 64 Mustang sitting on it about 6 feet in the air getting transmission work. The guys working on the flatbed truck had the ignition switch on with the transmission in 1st gear, and someone accidentally shorted the starter circuit, causing the engine to turn over. The truck lurched forward, smacked the back end of the Mustang, which sent the Mustang catapulting off the front of the lift. The front half of the car hit the 5-ft concrete retaining wall separating the lift from the front walkway, and sent the retaining wall crashing to the floor in front of where I was standing. Pieces of cinder block flew everywhere as I turned to run. Had I been any closer to the wall, it woulda nailed me.