Look around some more

You decide to check all of your surroundings, looking for anything that could be of use. Firstly you go over to the pool in the center of the room and upon closer inspection you can see that the pool looks quite deep, easily deep enough to submerge yourself completely. Secondly you check the crates and rummage around, most of them fall apart and you find nothing of use inside but in the last crate you find a silver pendant with a glowing, pink gem in the center. Outside of that you find nothing of interest in the room, everything else is just the monotonous grey of the stone walls with three seemingly identical tunnels.