Probably someone other than the victim hit the start button. I had a college job in a factory, latino guest voter had his hand on a 2 foot diameter machine gear and another guest voter turned on the machine. Guys hand went between two gears. When I saw him weeks later they had him on light duty driving a fork lift. His hand still looked attached but heavily bandaged, I guess there was enough clearance to save some of his hand or maybe they reattached the whole hand.