JamaisVu says:
To avoid the guitar and the hugging thereof, Cade searches the closet and taps the back and sides to see if they sound hollow.
The left side throws you off a second before you remember that's the side next to the hallway. The back and right echo a little, but it seems unlikely there's a passage or anything.
As you leave you're jumpscared a little by one of the objects in the cardboard box on the floor. A piece of canvas with a large green eye.
Also in the box are 3 dead flies and a small pile of mail. The top piece looks to be an invoice from a mail order bookseller. If you look closer:
[ +- ] Mail
The invoice is for 2 books Automatic Writing, and The Bell Signals Night.
The other 2 pieces of mail are an offer from an insurance agent and a postcard advertising a sale at a local hardware store.
Despite the addresses for both ads appearing local, neither business sounds familiar.