I use to work at a G.M. dealer when i was setting timing on a chevette. I had another guy put it in gear for me to check ruffness of motor so he puts it in reverse and didn't look to see if the parking brake was set. Well needless to say there was an open pit across from me we did alignments on and the car took off. I'm running after the car trying to hop inside and just barely got the car stopped as one of the back wheels falls into the pit. My heart was in my throatand a lil soil in my pants. Thank God nothing happened and we were able to push it up out of the pit.