The Left-Hand Way
This is the passage the writing on the landing wall recommends, and it is worn smoother than any of the others, so the advice has been taken often. Whether it was good advice is a separate question. A charcoal arrow points back the way you came; it has been drawn over an older arrow pointing the other way. There is an arch in the north wall, low and easy to miss.
Depth 3.
You are reading the dungeon, not walking it. Rooms are only created by people, and only from inside the maze.