It won't make the national or even local news for three reasons:
1) No one got shot--gore sells, good news does not.
2)It flys in the face of the liberal/antigun agenda of the news industry.
3) It demonstrates that in the vast majority of cases, successful use of a gun to dissuade a perpetrator occurs without a shot even being fired--the appearance of a gun and a committed gun owner is enough to stop most crimes.
The best defense against gun violence is more guns in the hands of more peaceful, honest, responsible people.