Exterior night scenes were shot day-for-night, but the sky and reflections of it were allowed in the frame, and they appear as bright white instead of black. This may have been intentional to emphasize the surreality of the film. See more
[X wanders through the hotel's corridors cataloging items he sees
Empty salons. Corridors. Salons. Doors. Doors. Salons. Empty chairs, deep armchairs, thick carpets. Heavy hangings. Stairs, steps. Steps, one after the other. Glass objects, objects still intact, empty glasses. A glass that falls, three, two, one, zero. Glass partition, letters.