Each tower landing offered five one-way doors, one safe and four hiding unknown dangers, with no going back.
Inside The Tower Maze every stairwell ends at a landing of five one-way doors, each said to hide a different danger. Choosing a door makes the other four vanish, and the way back is gone — consistent with the tower's rule that no one may descend until reaching the top, and that no teleporting or phasing is permitted inside.
Everly never learned what was behind the wrong doors, because Gordon's Compass of Vertical Labyrinth Management picked the safe one every single time, revealing only a small empty hallway and another set of stairs. Fifty flights of nothing at all — which is precisely how a compass built to sell a lie earns a crawler's trust. On the forced descent the landings drop to four doors, and seven of her ten mercenaries die in ten flights of them.
Landings ringed with five identical doors; once one is opened the others disappear, leaving a small bare hallway and stairs.
The tower's core mechanic — the illusion of lethal choice that made the compass seem indispensable.