Princess P's Invisibility Cap

Princess P was taken to a prison room while unconscious. She had no idea how to get out of the labyrinth of hallways. When she heard shouting behind her and then all around her, telling slaves and soldiers to raise the alarm and close the gates. No doubt every external door and window of the massive castle had been shut up at this point. There would likely be slaves positioned by the openings in the wall. They had no doubt that she was still within the walls, if not still trapped in the castle. Then the princess smiled. The doorway into the castle was blocked by slaves on either side, so the princess lined herself with the opening about 5 feet from the dwarf like a general