It's perfectly obvious what happened. Some guy's weapon jammed, so he started throwing the cartridges...
Funny, I never saw that option demonstrated in training. Probably a U.N. tactic. Fits with their usual level of effectiveness.
"Valor needs first strength, then a weapon."
-- J. R. R. Tolkien (1892-1973)
"Free men have arms; slaves do not."
-- William Blackstone (1723-1780)