I really could have done without reading that article. But since I did, I'll put in my 2.
I think Wink is right on as far as the legal aspects.
As far as the leaving the helicopter, I hope any law enforcement helicopter crew would land and take action in a case like this. As stated, some agencies don't make a habit of it. San Diego Sheriff's deputies will land and take action whenever it makes sense and is safe to do so. It is far more likely for us to land and assist a deputy or a citizen in the less populated, more rural areas due to the increased response time of the very few ground units.
In the urban areas, more often than not, it makes tactical sense for us to stay in the air, provide recon and direct and advise ground units whose response time is much better than in the rural areas.
Yeah, good job by the crew. But as many times as they hear "good job," they are wishing they weren't working that day. That goes for the citizens who witnessed this atrocity as well. I hope everybody gets some counseling for this because they are going to live with it for the rest of their lives.
Having a 3 year old and a 1 year old, this stuff really hits home more than usual.