Good mate of mine is in intensive care at the moment. And he is very experienced with cars and racing etc. So it shows it can happen to anyone.

He had a car on car ramps at the front and was under the car removing the tailshaft. However this was what was stopping the car comming off the ramps. When he dropped the shaft of the diff the vehicle rolled back and squashed him under the car.

8 Broken ribs, Punctured Lung, 2 Broken vertebre in back, shattered knee and broken leg. Not to mention concussion and bruises etc.

So be careful and dont get complacent.