[CORed]

When I took a class in confined space entry many years ago, they cited several horror stories involving tanks, sewer manholes, et cetera where somebody collapsed in bad air (toxic gas, insufficient oxygen, or whatever) and multiple people went in and died trying to rescue them. It seems to be almost instinctive to rush in to help somebody that's in trouble. I can understand the first person going in to attempt rescue, and maybe even the second, but you'd think that by the time somebody had seen four or five people go in and not come out, they'd figure out it wasn't such a good idea.