Removing the Blue Stone Triangle from around your neck, you press it into the granite wall. It is a perfect fit. You immediately feel a tremor running through the ledge on which you are standing, followed by the grinding noise of stone upon stone. The door opens, but after it has opened less than three feet, it begins to close.
Without a moment’s hesitation, you dive into the fortress and the door crashes shut behind you. (You may still keep the Blue Stone Triangle—you need not erase it from your Action Chart.)