Just before the police officer arrives the first time, Jaime uses her wedding ring to cut through the plastic zip-tie on her wrist, and then shoves the ring and zip-tie down the water drain. Later in the movie, when her husband comes back and is trying to talk her into giving him the money, Jamie is wearing her wedding ring again.
When Jamie is undressing for her shower, from the front there is a shower raining straight down in front of her face, but the view from behind does not show a shower raining down in front of her at all, even though the shower sound is continuous while switching between front and back view.
When the man is killed outside Jamie's room, his head is up against the opaque glass window in the door, and as he slides down he leaves a smear of blood from the back of his head. The only way that is possible is if the bullet exited the back of his head, which it didn't because the glass was still intact.
Jamie's shower was apparently turned on by opening a valve in her room using a large wrench, but when it was turned off no one was in her room to shut off the valve.