Once Bandu departs, the party manages to open a large oak door. Beyond it seems to be rocky walls as the tunnel leads into the rock beneath the lighthouse. Well, they find themselves in a large room with a door blocked by a portcullis. There is a red lever on the wall so they naturally pull the lever. Which springs the trap. Which lowers steel doors over the entrance and the door in front of them. Which starts the water pouring in through small fissures in the wall. They do try lot’s of things to get the water to stop. They do get the water to stop finally by prying open drains. But not before Ellie , the halfling loses some dignity points by riding her little 2’8” self on a floating barrel to keep from drowning in three feet of water.