Police Activity has a video showing not just the shooting, but the lead up and aftermath.
It shows the desperate struggle of 6-8 officers rendering aid trying to save his life, and the near breakdown of the officer who shot him.
But its flagged to all hell and you're not even allowed to use the share function.
He could have abandoned the gun in the ally way in plain sight for the police to see, then tossed his hands up and stood still. That might've been enough to save him.