High in a corner where the ceiling meets the wall, above the last row and off to the side of the screen, a small red rectangle holds its position through previews, feature, and credits alike, the one fixture in the room that never dims. Across six theaters on the same walking route, the sign occupies roughly the same coordinates relative to the door it marks, mounted a few feet above head height and angled slightly downward, so a rising audience finds the arrow before it finds the aisle. Inside the box, a plain arrow, backlit red, points toward whichever exit the door code and fire marshal have agreed is nearest; the box runs on a battery trickle-charged off the building's power, and once a year a fire marshal confirms that the red survives a cut breaker.
During the film itself, the sign alone has no relationship to what is showing, unconcerned with plot, unmoved by the ending. Audiences look at it exactly twice: once on the way in, when it is the brightest thing in a dark room, and once at the end, when it stops being scenery and becomes an instruction. Credits roll, house lights rise, and the arrow points where it pointed two hours ago.