From the Introduction:
This little dungeon is a nexus of magical portals and connects no less than four of them. At the top level a portal glowing blue exits onto a small rocky island floating in the center of the room making up the largest part of this nexus. Only a narrow rock bridge leads to an archway in a sidewall and the ramp behind it leading down to the middle level.
On the middle level a bridge made from steel grating leads across the central room from one side to the other. Only observant travelers will notice the arrow slits to both sides of the bridge or the secret doors leading to the guardrooms behind those arrow slits. On the other side of this bridge another archway connects to a ramp leading down to the bottom level of the nexus.
The bottom level of the nexus holds the other portals. One is positioned directly across from the archway leading in from the ramp and one each to the left and the right of this entrance. These portals all glow in a sinister red light, which mostly obscures the devastated landscapes behind these doorways.