One thing that stuck in my mind watching the video was how diving wearing a mask our peripheral vision is greatly reduced, yet we're in a '3-D World,' so to speak, where things can come at us from above, not just on our level (basically, on land it's usually a fairly 2-D experience, unless you're dealing with birds).
A 15' shark swimming around us, and other sharks of decent size doing likewise, in a situation where I couldn't keep them under constant observation even in close quarters, seems a bit anxiety provoking.
Haven't done a shark dive yet. If I ever do, I imagine I'll think of this.
Richard.