If you don't come home with data, you've done nothing.
— William Stone
Caves are whimsical things, and geology on a local scale is random and unpredictable.
There are plenty of people on Earth. It's not like the human race is going to disappear if a few people don't come back. Exploration is dangerous.
Cave divers, of course, deal with an elevated level of risk, and the most that I can say here is that we tend to conduct our work at the bottom of a deep cave on an extremely conservative basis with heavy levels of backup equipment and a policy to abort if any single person doesn't like the situation underwater at any time during the mission.
Many people think all I do is some random engineering work in between caving expeditions. It's been far more deliberate than that.
Generally speaking, moving water is the most dangerous thing you can encounter underground.
