Chalk one up for the good guys. Faculty at Dixon High School in Dixon, Illinois thought they’d heard fireworks yesterday morning, but school resource officer Mark Dallas knew otherwise. He confronted 19-year-old Matthew Milby, who had opened fire in the school, forcing him to flee and eventually hitting him in an exchange of gunfire. The only casualty was the gunman:

An Illinois school resource officer stopped an armed teenager at a high school Wednesday morning, according to the local police chief, who applauded the officer for saving “countless” lives.

When the 19-year-old suspect fired several shots near a gym at Dixon High School, the school resource officer reported the incident to authorities and then confronted the gunman, Dixon police chief Steven Howell said at a news conference.

When confronted, the suspect — a former student at Dixon High School — started running away, and the officer pursued him, Howell said. The suspect shot several rounds at the officer, and the officer then returned fire, hitting the gunman, the chief added.

Illinois governor Bruce Rauner praised Dallas’ quick and effective defense of students at Dixon High:

Today, we should all be very thankful to school resource officer Mark Dallas for his bravery and quick action to immediately diffuse a dangerous situation at Dixon High School.

— Governor Rauner (@GovRauner) May 16, 2018

As one law enforcement officer noted in ABC’s report, everything went right in this case, when a whole lot of things could have gone wrong. That’s clearly true, but first one thing has to happen before anything can go right — the shooter has to be confronted with deadly force. Mass shooters don’t pick schools as targets because they want to engage in an equal fight; they choose schools because they believe them to be soft targets without the ability to engage in return. They want easy targets, not a gun battle, because they are cowards.

With this as the key of any defense of any perceived soft targets, it’s clear why having armed and trained personnel on hand makes more sense than declaring areas “gun-free zones” and forbidding it. In this case, a school resource officer was on hand, but a teacher who’s willing to carry and take the extra training necessary for the task should be allowed to participate in effective defense and self-defense, too. That would assure an even faster confrontation with cowards who want to confront only defenseless children and staff and limit even further the damage they can cause.

Bad guys with guns usually only get stopped by good guys with guns. And Mark Dallas proved himself one of the best of the good guys yesterday.