What gets me about the Leviathan Battle Story is the fact that Nautilus makes the assumption that the Leviathan would be accustomed to cold water. Putting aside, you know, logic and science if shit for just a few seconds so we can assume the Leviathan creature did/does exist, and DID live in the very deep ocean... it could well be USED to a very hot-water climate. The sea floor in a lot of places along ocean trenches and faults is RIFE with volcanic vents that eject water and gases at temperatures well beyond that of mere boiling water.
Yeah, the deep sea doesn't get enough sun to warm it THAT way, but it still manages to produce scalding hot water in other ways.
(Also, I am high.)