The Green Cistern
Standing water covers the floor to the depth of a finger, and it is perfectly still. You are in a small chamber: 1 pace one way and 2 paces the other. There is a hole in the floor, hand-sized, and it goes down further than seems reasonable.
Depth 14.
You are reading the dungeon, not walking it. Rooms are only created by people, and only from inside the maze.