PLV works very well in practice to induce hypothermia. You only have to intubate, so you can field a kit any semi-skilled paramedical can use.
Must take care of volu/barotrauma, though. This stuff has twice the density of water, after all.
This is pretty cool. It's like in that movie, I forget the title, with the liquid sentient creatures that decide to kill everyone with a massive tidal wave but then change their minds.
Yeah, The Abyss.
This liquid breathing stuff was also used in Dan Brown's new book, The Lost Symbol