What ho- oh, you now see two holes in your safe. Those weren't there before, or at least you don't think they were. You only now see them because light emits from them, and your room wasn't dark before, so the holes are more visible. That must be it, the light from PS' room must be filtering into yours through these holes.
You look through them. Just as you suspected, PS' room. He looks a little busy right now, so bothering him is out of the question. Not that you would bother him at all, you're quite an introvert, but he's busy, and that's a better excuse than you get anxious when talking to people.