Generally, the responding citizen(s) use reasonable minimal force, often they do not have to discharge their weapon. They stop the incident and often are able to hold the perp for LEO's arrival. Unfortunately, we can only speculate on the amount of damage prevented.
Admittedly, the citizens in this incident were ex-LEO's, and had that training and experience, but plain legal-CCW citizens perform in the same manner, and you will see little coverage of that in the media.