Dinah zip-tied a high-powered LED light to the inner hatch of the airlock, then closed it. She opened the valve that dumped its air into space, allowing it to "fill up" with vacuum, and then actuated the lever—a simple mechanical linkage—that flipped the outer hatch open. She could see the white glow of the LED reflecting against the plastic of Tekla’s Luk bubble a few meters away, and she saw Tekla’s head turn as the light got her attention.