I am a 24 yr. mental health counselor and 9 yr. police officer prior to my present profession.
As for a cop perspective, cops hate those DV calls for they can come to save the victim by arresting the abuser only to have the victim turn on them. So bad situation even for those that do it for pay. From a psychological perspective, there are a lot of strange dynamics in relationships with DV. Sometimes, the victim does not view themselves as a victim, the abuser is a controller usually, so lot of stuff. Usually, what you may see is "same song, 15th verse", meaning it has happened many times.
A permit does not make you a cop and frankly, calling 911 is more than many would do. Making a call is good, but don't go walking into someone else's fight.It is not right, but still, you just don't know. Most cops will not roll up and pull a weapon either. If you are there, holding a gun on someone in a parking lot, when a cop rolls up, the dispatcher may not give the officer the full details. You might get shot or arrested. It is not worth the risks to you or your family. 911 and let the pros take it.