Deadly Fight - What would you do?

I've written before about the need for concealed carry permit holders to think through potential situations they could encounter and which ones would require them to draw their gun and which ones would be better for them to avoid and let the police handle.

I was reminded of this principle recently when I saw an article about a ​private citizen who stopped a potentially deadly fight in a Wal-Mart parking lot without firing a shot.  I'm very glad the situation turned out well for the concealed carrier here but it could have easily gone wrong.  

The permit holder saw a fight between two men, one armed with a baseball bat and one with a knife.  He then drew his gun and told the men to stop fighting.  I would not recommend that you handle a situation like this similarly.  Here are some of the questions that came to my mind:

1. How do you know who is the "good guy" in a scenario like this?  
2.  What happens if the fighters don't stop?  Was the concealed carrier ready to shoot the men if they didn't listen to his commands?  If he shoots the fighters, he will likely be in legal trouble for escalating the situation.
3.  What would he do if they start attacking him?  Again, the situation goes from bad to worse.

Clearly, this is a potentially deadly situation and I would not have blamed the man for ensuring his handgun was easily accessible to protect HIMSELF.  When I think through this situation, I would try to get a safe distance away from the fight (maybe in my car) and call the police.