He had spinach last night, his Wheaties in the morning and saw the Incredible Hulk do it, so he was thinking it would work out.
On the other hand he probably had done it that way dozens, if not hundreds of times, before and he had always gotten away with it. If he was alert and quick on his feet there was probably some chance he could have caught sight of the pipe rolling and ducked under it and sheltered under the trailer.
Didn't work out that way.
I have taken similar risks. I would like to think well of my self, that the actual risk was somehow less and, of course, I always had my ducklings more firmly in line and was more on the ball than this guy, I suspect that none of that was always true. Sometimes I was swift and sure. Other times all that saved me from death or disability was dumb luck.
I can joke at this guys end. But not without feeling that it could have been me.