Now what actually happens, now as I say I'm going to the far end, your casualty may literally shriek as they go down, now this is the person that has no warning at all, they may shriek as they go down and it's the air that's coming out of the body, they will go rigid as every muscle clenches, the teeth clench, the muscles go rigid, erm and they're going to be very, very blue because erm, because er they've stopped breathing which seems like an eternity.