All the officer needs to do is prove that he felt his life was in danger. If he believed that the airman could have injured him in any way...he'll more than likely recieve psych evaluations and two weeks unpaid leave.
Now, the community may put pressure on the department to get rid of this guy. However, it'd be a really tough case to prove that the officer shot the guy for no reason. Even with video.
Either way, both sides lose. The department comes off looking awful and a young man is hospitalized for something that could have been avoided IF, and only IF the proper techniques were applied.
Most departments across the US are starting to train officers for this. I had to take several ethics classes, most of which teach you how to handle a situation similiar to this.