Probably enough of bashing of JW, it's easy in hindsight to do the self preservation thing first, however, in reality, sometimes adrenaline/instincts take over.
I've experienced both, from quickly assessing a situation and going in, to holding back and doing nothing. Usually whatever you do, someone will find/think something about your actions was wrong.
As to the original part of JW's comment, I think the fella fell in a hole outside a house, and whilst its a confined space, most likely not a gaseous environment; but who knows lol. I bet he yelled out to the fella before he lowered the ladder, which could of given an indication as for potential dangers?