Don't forget a nice torture chamber.
"...as you pass into the narrow, platinum plated room, you see a raw gold ore lever set at the end. A small note hangs on it: Lever to be used only be Urist McHammerdorf."
Pulling the lever results in the PC being dropped 2 z levels, breaking both ankles.
"While you look around, holding your legs in agony, you see a set of stairs climbing out of the pit. These may have been used by the designers when they built this trap, or by the cleaners who would need to come by after its use."
Climbing the stairs leads you up one level above the room you dropped from, and passes over a pressure plate (search check needed to spot and avoid) connected to a bridge, which drops the player back through the platinum room, through the trap door, and back into the bottom level (a 3 z level drop), breaking both legs (or wrists depending on how they fell).
"You reach the top of the stairs, a dark and narrow rough stone hallway shows signs of light at the end. In your hurried crawl towards freedom, you fail to see the pressure plate. As the trap door opens beneath you, you can see straight down into the room you fell into before. Looks like you'll be falling an extra floor to the bottom this time."
The only way out is to either avoid the pressure plate, or get a friend to wall climb to the lever, push it the other way to close the lower trap door, and fall back into the platinum room, only bruising yourself.