Shoebox-sized Tripper-proof trap that floods a room with Sheol fire, chained in sequence to a dead man's switch.
Eight of these ring the observation deck of the Surgical Theater, mounted up out of reach and all angled down at the floor. Each is the size of a shoe box, far larger than the usual Lego-sized Trap Modules, and reads more like a weapon than a trap. The info box carries three warnings: it is Tripper-proof, it is chained in a sequence so that removing or triggering one activates all the rest, and it has a dead man's switch attached to Architect Houston — kill him and they all fire.
They fire Sheol Fire into the room, incinerating everything instantly, triggered by anyone unaffiliated with The Madness setting foot on the floor. Carl has never seen or heard of anything like it. The setup makes Houston effectively unkillable without burning Burcu alive, forcing Carl to cross the room by Walk on Air; when his feet finally touch the tile the whole sequence goes off, killing Burcu, torching the castle, and leaving only Gloom Wraith Phase as his way out.
Eight gleaming shoebox-sized modules mounted along the rim of the theater's raised observation deck, all facing downward into the room.
Houston's insurance policy, turning the surgical theater into a room nobody can enter and nobody can survive.