"Half a mile underground, floating in the Japanese subterranean neutrino detection chamber"
You might like to hear the following things: People have fallen in to the water on more than one occasion. The human body does not float so well in ultrapure water, but obviously there are lifejackets. Access in and out of the tank is two at a time on a hanging gondola which is winched up and down slowly. There is no second way out. In the case of an emergency the only way out is via that gondola. The phototubes have a tendency to implode if shocked as they are glass under vacuum, which they did catastrophically in 2002 nearly ending the experiment. Being next to one when it implodes could lead to serious injuries.