At the very least this officer should be fired and at best tried for attempted manslaughter. Excessive use of force is an irresponsibility afforded by exactly the attitude expressed by his superior. If there is no punishment for police officers with criminal intent, then of course this type of thing will occur. People in positions of authority will always abuse their power if they have no proper oversight. I say that officer should be charged and held fully accountable for his actions in a court of law.
Then maybe other officers may instead choose to ask questions first and THEN shoot later.