At a high school just outside of Phoenix, a madman stalked the halls. Suddenly, shots rang out and people started screaming.
It was just a training exercise, but the situation is every parent's worst nightmare, which is why controversial Sheriff Joe Arpaio of Maricopa County, Ariz., has called on his all-volunteer sheriff posse -- 3,000 civilians strong -- to keep Maricopa County kids safe.
Today, these men and women, many of whom are retirees, were learning tactics that they might have to use to bring down the next school shooter. Their coach was '90s action film legend Steven Seagal.
"For every second that goes by, I told you this, you are going to have dead children," Seagal told the volunteers.
The "Out For Justice" star knows a thing or two about simulated shootings, but in this case he was not acting. He, too, was a full-fledged member of Arpaio's official posse.
The sheriff's big idea is to have his posse members patrol the county schools. Of the 3,000 posse men and women, 500 were certified to be armed. They can wear sheriff uniforms and drive marked cars, and it is all perfectly legal. In fact, several states have civilians in official sheriff posses conducting patrols.
The posse school patrol was only the latest high-profile gambit for the man they call "Sheriff Joe," but now the stakes are higher than ever.
Five minutes is all it took for the horror to unfold at Sandy Hook Elementary School in Newtown, Conn. But since the massacre of 20 children at Sandy Hook, there have been other school shootings in California, Georgia and Texas, just to name a few.
So now the great debate is joined: How can we protect our children?
This week, the National Rifle Association offered one answer: Arm teachers.
But in Arizona, Sheriff Joe has decided to take matters into his own hands with his school patrol posse.
"If we have to take action, we will take action," he told "Nightline." "We will go on the school grounds, and we will go into the schools if there is some type of catastrophe that's going to happen."
If you haven't heard of Sheriff Joe, well, that is almost hard to believe.
Since he was elected sheriff of Maricopa County in 1992, Arpaio has been a publicity machine -- on immigration, prisoners' rights, gun control, you name it, this man has found a way into the national discussion. Now he has an angle on school safety, even appearing in promo clip during an NRA news special, but he said he is not out to do the NRA's bidding.
"This is one sheriff who is a lone ranger," Arpaio said. "I don't copy other people, what they do. I think my 20-year history shows that. So if you think I copied people? They copy me. I'm not trying to brag."
The school posse will patrol near schools in the mostly rural, unincorporated towns of Maricopa County.
Some people in different parts of the country might hear the word "posse" and think it is an undisciplined gang going around helter-skelter without proper police supervision, and potentially endangering the community, but Arpaio said he doesn't see it that way.
"Maybe [those people] are watching too many old cowboy movies, but the concept is the same," he said. "Instead of going after horse thieves, we go after car thieves and anybody else that violates the law."