Had something like that happen to teen age me at the Kinston NC drag strip. They allowed street cars to participate sometimes. I was in the pits with my dad & younger brother. We're leaning on the fence where they do burn outs and a Mustang Mach 1 was setting up to smoke his tires and the drive shaft came out and hit the fence at our feet. If we had been standing flat instead of leaning I'm sure it would have broken our legs.