Yea there was something caught in the chain and I thought I could get it out before it went around, well, while trying to wedge the piece of shingle out of the chain my hand became stuck and pretty much started carrying me up the chain drive by my hand till it ripped out of it. Pretty painful and since I cannt take any narcotic pain meds....my and my buddy aleve got to know each other a lot better. But yea I would have just gotten out of the way of the shelf...when we stand back and look at the dump things we do, its always the same question...why did I do that?