"Heh. I was gonna say it sounds like "The DaVinci Code," until I realized this is a pretty common technique. "Foreshadowing" or either "presaging" comes to mind; but maybe too subtle?"

This isn't really what I think of as foreshadowing, somehow. To me, that term implies something that happens early in a book or movie that is very like something that happens later on, but perhaps less intense than the later plot development. I think of a particularly lousy movie I saw once ("Fun House", I believe it was) where the heroine is taking a shower and you think she's about to be hacked to bits and it's only her brother annoying her. Brian DiPalma, a director I really don't like, pulls that stunt pretty often.