One year ago today, Jacob Tyler Roberts ran into the Clackamas Town Center Mall armed with a stolen Stag Arms rifle, carrying multiple magazines of ammunition in a tactical vest. He opened fire near the food court on the upper level, shooting three victims, two of them fatally, before his weapon jammed.

It was as Roberts was attempting to clear his weapon that concealed carrier Nick Meli drew his Glock 22 and took careful aim at Roberts’s head.

Ultimately, Meli didn’t pull the trigger to launch a .40-caliber bullet towards Roberts, because he saw people downrange that could be hit if he fired. Instead, Meli moved to cover and a better position. He says that Roberts saw him at this time. Roberts then ran down a flight of stairs and committed suicide.

Committing suicide when threatened with the possibility of being shot by someone else or captured is a common trait for mass shooters and would be mass shooters like Roberts. Klebold and Harris at Columbine, Cho at Virginia Tech, Lanza at Sandy Hook, Hennard at Luby’s Cafeteria, and other mass shooters followed this pattern, and Roberts proved to be no different.

Merely seeing Meli was apparently enough to cause Roberts to flee to a more isolated location so that he could take his life on his own terms. When responding officers discovered Meli’s body, he still had multiple magazines of ammunition for the rifle. There is no way of telling how many more lives might have been lost if concealed carrier Meli hadn’t thwarted Roberts’s shooting spree shortly after it began.

Armed citizens save lives hundreds of thousands to millions of times each year, according to criminologists on both ends of the ideological spectrum. Most times, the mere presence of a firearm is enough to stop an attack.

Nick Meli was careful not to fire because he was more interested in protecting the living than avenging the dead. Of course, that is the reason most Americans own firearms.