Cave And Underground Lake In Canyon Of The Lost - Broken Button?

I originally had this in the questions section, but I don't think it fits in there.

So I happened upon this cave in the canyon of the lost:


Inside is a large underground lake that, curiously, has no way to escape (naturally, without class abilities) that I can find.


There is a button on one of the walls at lake level, but I can't find out what it does (if it works?)


There is another room behind the lake that contains a smaller lake and a building of sorts:


In the center of the "building" is a small room:


In multiple areas in both lakes, mobs can be seen very close to the walls of the cave. These seem to be mobs from the earth and water minidungeons.


(sabertooth pigs behind this wall, and one even spawned inside the room with me)


(shimmering jellyfish below the floor of lake 2's cave)

I also saw some rivermen.

So is this supposed to be the entrance to one of those dungeons (broken button perhaps, or something I'm missing)? Or is it something else entirely? There are no loot chests inside, except for one low tier chest in the entrance.

 

Lol so much Corkus stuff

-bump