The players enter this room from either direction, passing through a set of double doors. A heavy portcullis bars both entrances, but each of these is easily raised using a mechanical winch just outside the room (not pictured). Thus, anyone who enters the room must find a way to raise the other portcullis to leave via the other side.
This large square room has a domed ceiling. The floor is crossed with deep grooves one foot thick which divide the chamber into four equal parts. The grooves continue up the walls and across the domed ceiling. The chamber is decorated throughout with patterns drawn with strange and ancient text. Each corner has a decorative pillar, carved with the appearance of a fierce demon, and embedded with a lever.
Pulling any one lever causes both portcullis winches to release, trapping the player characters inside. Pulling all four at once raises both winches, if each character speaks a password in the demonic tongue. If all four are pulled at once but the password is not spoken, a double trap is triggered. First, a wall of blades trap springs from the floor along the groove, dividing the room into four equal parts, most likely with one character in each. Second, the runes drawn on the ground glow and one demon is summoned into each quarter.
Both effects last for one minute, after which they vanish as quickly as they appeared and the portcullis rises on each side. Player characters can pass through the wall of blades, but doing so incurs damage.