In some of the episodes, Scully tapes an 'x' on Mulders window. I remember one of the episodes, was when Mulder was trapped on the train car with this other man, and there was a lepper that was trying to be smuggled back to Japan. There was a bomb on the train car and it took a combination to unlock it. Scully was looking at the tape that Mulder bought before that showed a man typing in the combination. Right before she watches the video, she tapes the 'x' on the window. I dont know if its a sign for anything or not? If anyone knows, that info would be nice to know!!!