Viewers are kept guessing until the end what's keeping this man very edgy, agitated and nervous. Even as there are shots of moving hangers in the closet, a door being closed and a lock being opened, still viewers can't make up their minds if it's a physical person lurking in the dark or a ghostly presence. After all, it may all just be in the person's imagination. Details like the droplets of water from the faucet create tension for this man and even at the final scene we don't hear a single shriek or shout to convey that he's been attacked by anything or anyone. Engrossing to watch!