@codinghorror: Looks deceive, mortars IME can be VERY dangerous. The video doesn’t show it very well, but those fireworks are quite powerful.
As the video shows, safety tip number 1: Do not look down the tube - that invites a mortar shot to the face.
Safety tip #2: DO NOT put the shell in the tube upside down. Classic drunk-mistake. That WILL cause the shell to blow the tube up spectacularly.
Tip #3, goes without saying: Mortars do not make good hats.
I’m guessing the gentleman in the story violated both rules 2 and 3 - he put the mortar in the tube upside down, and held the tube over his head, and as a result, the shell blew his head off.