Not MC Related - but...
Many years ago was working on the engine of my old Case bull dozer. Wanted to fire up the engine to check my work. I was standing on the left hand track, reached in and moved the gear shift to assure the transmission was in neutral. Clicked on the key, hit the start button, and the engine fired right up.
Problem was, the transmission was NOT in neutral.

Sucker took off in 2nd gear at about 1/2 throttle. The track whipped out from under my feet, throwing me to the ground, on my back.

Did I mention that I was about 75 feet from my house, and the dozer was aimed at the living room?
I jumped up, and ran after the Yellow Peril (remember, this was many years ago). Lept up onto the draw hitch, reached over the seat and turned off the key. The machine sputtered to a stop about 10 feet from the porch. I was lucky the damned thing didn't run me down.
I don't believe I ever told the (ex)wife about this incident.