The underwater hatch or outpost that Jack has been entrapped in has recieved the name "The Hydra Station". Hmm Hydra, Hydra is a mythical creature who battled Hercales in a swamp near Lake Lerna.
The Hydra was simular to a snake, and had many heads, it was simular to the beast described in the book of Revelations (But alot smaller..Heh.).
Also Hydra is a name of a Constellation.
Thats just the gist of the Hydra story, if you want to learn the boring specific details of the hydra creature go here:
Lernaean Hydra - Wikipedia, the free encyclopedia