Close the bedroom door!

I never understood why they didn't eventually close the bedroom door and keep a lamp on. Yes, I understand it adds to the plot, and that it would ruin their filming, and that closing the door wouldn't stop something from coming in if it is in spirit form, but towards the end, they had to have been getting pretty creeped out, if not by the middle of the movie or sooner. At least the door and light would ease fear. I was especially surprised that the female in the couple was the one constantly sleeping on the door side. She wasn't as enthusiastic about the filming and was more easily frightened. They should have at least switched bed sides.