Unfortunately, Leviathan makes it clear she won't be giving any help. The water is part of the trials, and those who cannot prove their worth have no business proceeding any further inside.

"I think that's a no..." Uendo, likewise a Summoner, shakes his head. Calling on an Eidolon doesn't seem to be the answer. "Could the water have dripped from the ceiling? It is pretty damp here..."

There's nothing of note inside the side rooms themselves. However, while following the remains of the walls, they may come across an old device -- a lever, and a circle-shaped cavity about three inches across and one inch deep. Trying to activate the lever won't have any visible effect...