The original script is here: A person is about to open a door. The person hears a sound and becomes mildly concerned. The person finds the door locked and searches for their keys, or the way in which the door needs to be opened or unlocked. The person hears the sound and becomes mildly apprehensive. As the filmmaker, your goal is to build tension and growing panic, using any visual element or device that you can think of.
Your film should have the following characteristics:
-Neither the character nor the audience ever sees the source of the sound.
-The film can have only one actor.
-The film may not exceed 90 seconds.
-The entire film should focus near a door.
-There should be a surprise