ARLINGTON, Texas -- Inside a nondescript strip mall on Pioneer Parkway, Go Strapped Firearms sees a steady stream of business.
Classes are often sold out as men and women look to earn their Texas License to Carry, or TLC.
Over the past eight weeks, though, instructor Byran Proctor has seen a spike in a new type of student: teachers.
"This one [course] filled up within 12 hours of announcing it," said Proctor.
The teachers are part of a course Proctor only started offering last year that targets educators who already carry an LTC.
"Everything we do is through guidelines from TX DPS," Proctor explained. "Teachers, you're not there to find the active shooter, or hunt them down, they're there to protect the kids."
During a recent two-day course, WFAA saw local men and women of the classroom go through a range of live-action training and simulation that mimic a school attack.
"It gets up the heart rate, and a little bit of tunnel vision," said Norman Rangel, who is a principal at a local private school.
Rangel says his school hasn't fully decided whether anyone on campus should carry. Should that day come, he wants to be ready in the wake of tragedies like Parkland.
"The course, it definitely brings awareness to how serious this is," he said.
Jeremiah Chambers is a local special education teacher. He said he wasn't interested in debating the politics of carrying on campus, but rather wanted to be prepared in case of the worst "what if."
"That's what we signed up for. As a teacher, those kids are like our kids," said Chambers.
During each simulation, the teachers pit themselves against "mock" intruders who are outfitted with body-armor, knives, and AR-15's.
It's loud.
Chaotic.
And that's entirely the point.
"We want to make it real," said Proctor. "We practice first avoid, then deny, and then defend."
The approach teaches educators to only go for their weapon as a last resort, if there are no available exits or ways to effectively blockade a classroom.
Proctor is keenly aware a debate is raging across the country about whether teachers, or administrators, should carry on campus.
As a former police officer and well-known instructor, he was one of a select few granted permission to officially start the educator training.
Some local districts, like Argyle and Keene ISD's, have been public about their decisions to arm teachers that volunteer.
Proctor says he thinks larger districts are getting ready to at least debate the idea.
"A lot of these teachers today don't have districts that allow it. They'll have to go there and try to implement this," said Proctor.
The men and women WFAA met were largely paying for the course out of their own pocket, although some schools may eventually fund the training.
Texas DPS has authorized roughly two dozen similar courses through licensed LTC instructors around the state.