It may have actually been that deep.
When I was a kid in the early 60s or maybe late 50s a diver drowned in Morrison Springs at something close to 300 feet. I guess my memory could be off a bit.
Lloyd Bridges came but when he found out how deep he was, he said it was too deep.
It took a while but finally some kids from Auburn got the body out.
This brings to mind the old aviator’s saying - “There are old pilots, and there are bold pilots, but there are few old, bold pilots.”
To me this looks like pure craziness, but then I’m somewhat claustrophobic so the idea of deep cave diving, or even spelunking, sends shivers through me. These guys died in an unusual place and way, but I could just as easily kill myself while pushing my limits on the road on my motorcycle. I’ll presume that these guys weren’t idiots, and apparently they were experienced, so I guess something unexpectedly went wrong.
At least if I ever manage to kill myself on my motorcycle, it won’t likely require a team of people to risk their lives to recover my body.