How is it that this happened? What made the primer go off? Simple rolling off the table to the floor doesn't seem like it should be enough. Not to mention it would appear based on the roll, that the round didnt land primer straight down on something (not that that should make it go off anyway).
The video doesn't show but I wonder what kind of damage it could have done? I can't imagine the pellets projecting much more than a foot or two.