I think what struck me was how the sound of the last shot just kind of cut off instead of echoing like the others. From there you can just look and see other inconsistencies.
Ah, you are correct with the sound. I didn't catch that when I first watched it. Also noticed what slash noted on my second/third watch, there was a comment on that website, something about a compressed air tube and that shotgun guy was concealing it, however I didn't see anything like that when I watched it. Perhaps someone else will.
