Stairwell vestibules are outside the active level and reject all trap placement, including teleport anchors.
Carl asks Florin to enter his exit early and test direct trap placement. The chamber is approximately five meters square with a luminous stairwell in its center, resembling the floor's opening globe room.
When Florin drops a trap, the system rejects it because the chamber lies outside the level. Mordecai says stairwell restrictions are stricter than saferoom rules and doubts even a trap mounted on a walking automaton could bypass them.
The rule prevents Carl from sending allies or himself directly inside a secured exit and forces intervention on the active-floor side.
A small vestibule with glowing stairs surrounded by a boundary that rejects a teleport rune.
The exclusion closes the safest version of Carl's teleport rescue plan and preserves the need to fight for doors.