the prostitute and the telephone cord
I think there's significance in showing the prostitute carefully stepping over the telephone cord in the hotel room. From that moment on Harry's sense of reality - and the viewer's trust in what they're seeing - becomes distorted and unreliable. He is desperate for the intimacy he has lost with his wife, and the prostitute offers this, but she doesn't follow through with her kiss, and Harry remains lost and confused.
I think I'm talking through my arse. But it sounded good for a while.
"Almost nobody dances sober, unless they happen to be insane."
H. P. Lovecraft