The Black Citadel

You take out the map of the spire again for another look. Below you is the first floor, and you're now situated on the second floor. You can make out eight major and four minor rooms on the first floor according to the diagram. The second floor contains six major and two minor rooms. While the third floor contains only three major rooms. The map shows this room, and another room drawn inside its perimeter. The medusa's lair likewise, has a second room drawn inside its perimeter. The vampire's lair must have a secret room someplace that can be entered somehow.