That the officer was not injured doesn’t mean he wouldn’t have been had he not done what he did.
We don’t know what happened between the deceased and the officer who deceased him.
What we do know is a whole lotta idiots are doing a whole lot of evil which is in no way connected to nor justified by the initial shooting.
He did what he did out in the open in broad daylight in a residential neighborhood with a lot of people watching —
There are enough witnesses to piece together what happened especially when they are corroborated by the incontrovertible forensic evidence.