There are stairs leading into this room. you start down them only to fall to the ground since the stairs drop off the wall. Its too dark to see much in here, but there is a large body of water in the room, and a vicious current is sucking water down, as well as forcing it back up. Surely you would die if you entered it, so you look around for anything else...
(you must Bring the Silver Wing To Battle The Mighty Lugia)