Go to the part where Boromir is getting shot at by the Uruk-Hai with arrows. Here's the slip-up: When Boromir gets hit by the second arrow, look between the two arrows. You will see a dark stain. If you can't tell, it's blood. That blood indicates where the third arrow will strike Boromir before it actually happens. Feel free to flame me if I'm wrong, but I see this slip-up every time I watch the movie.