I was out wheeling with some buddies one time and had a friend roll his jeep.. His passenger thought it would be wise to grab the roll bar above him and proceed to get his fingers smashed... He lost his birdy finger on his right hand. Its instinct to want to try to brace yourself before impact but a person has to fight the urge to put any limbs outside the vehicle.. Mind over matter I guess or learn the hard way like my friends buddy did..