From the Introduction: Beyond the doors lies a peculiar kind of room. The corridor continues to cross it, after a fashion, along it's axis intersected by another similar walkway at its center. Instead of walls you find steep drops on either side, with only a few solid columns every few feet. Waves of oppressive heat waft of the molten rock blubbering a few feet below the gangway and its glow plunges the room into a hellish light. Narrow guard platforms line the long walls of the room separated from the central walkway by several feet of glowing molten rock, open door frames leading into much more spacious guardrooms behind them. Quite obviously this room is some kind of important junction in this dungeon, and it was built to make sure no one crossing it would go unnoticed.