We learn about the door to nowhere concept early in the film from Elizabeth Gracen’s character, Beth, who says it was part of Feng shui and a vortex of bad energy. If you look closely throughout the film, the door — which, as the name implies, doesn’t really go anywhere — is used by several characters who should definitely not be in the house.

As Byrkit explained it, when the characters Hugh (Hugo Armstrong) and Amir (Alex Manugian) leave the house and take the box with them, they leave through that door to nowhere and “they put an oven mitt in [the box],” that’s because, as we learn towards the end of the film, this is the oven mitt house, which the characters Emily (Emily Foxler), Kevin (Maury Sterling), and Laurie (Lauren Maher) don’t realize. “If they would have just looked at the table and said, ‘Why is there an oven mitt here instead of a ping pong paddle?,’ it would have gone very differently, but they didn’t,” Byrkit noted. “They didn’t notice, and the actors didn’t either.'” 

Throughout the film, we learn that there are “good” and “bad” versions of the characters, and those who enter through the door to nowhere are all bad — making this a great hint of what is going on. When we hear Hugh pounding on the door, it’s our first hint that he is not who he seems. Likewise, our Emily uses that door at the end of the film to kill her doppelganger and steal her spot in a different reality. Beth was right, and whoever is near the door has bad energy and is someone with unresolved issues. 

Before the surprise sequel to “Coherence” arrives, you should rewatch the original movie with this in mind.