I have stepped into a violent incident, where I held back an
elderly woman from jumping in to save here niece in a street
brawl. No way was I going to attempt to break up the fight.
The niece got beat up pretty badly and I accompanied her to the
hospital.

The long and short of it is, as a foreigner don't try to directly intervene.
However, you may be able to mitigate the damage by creative assistance
on the sideline. At least you are confident no one will shoot you.