I guess I take for granted sometimes that not everyone is knowledgeable of human anatomy.
Not sure about my opinion of the whole "you'll be sued for shooting the BG too many times" line at the end, though. I thought that was a bit much. If you shot them 12 times and they were still a threat on the 11th hit, but stopped after the 12th, then it was a justified shoot.
No such thing as a guaranteed 1 shot stop and all that.