Sorry, Rob, I disagree. That was no accident in any normal sense. No one's gun went off accidentally. Those cops let killer training and panic take over and simply kept firing because thinking was not part of their weapons training. It was not premeditated, but those cops were psyched up to kill. One of them saw or thought he saw a weapon, and fired, then the others joined in almost from reflex. The first shooter could have fired once; the others could have chosen not to fire. But their training (see my note about military style training above) along with some panic kept them firing.