(NewsNation) — Hours after a gunman killed 19 children and two adults in an elementary school in Uvalde, Texas, Lily Purich walked into her own classroom at her Illinois school, met by the faces of worried second graders with questions about their safety.

“I had a couple of kids ask me, ‘Hey, Miss P., are we going to review our lockdown drills today?’” Purich said. “And there was no plan to from the school, but because my kids were asking about it, I wanted to make them feel comfortable and safe.”

Purich is 25 and on her third year of teaching. She knew at the age of 5 that it was the career path she’d take. By the time she was in high school, watching live coverage of the deadly shooting at Sandy Hook Elementary School, she understood it was a career that could put her life in danger.

“Sometimes I think, ‘I don’t want to die,’” Purich said. “I know that if it came down to it, I would put my life in front of my children. But I don’t want to have to make that choice.”

For years, schools have implemented various forms of active threat trainings to prepare for the worst, but the strategies have repeatedly changed.

Today, active shooter preparedness goes beyond the previous “one-size-fits-all” approach of hunkering down in the classroom, said Pete Blair, executive director of the Advanced Law Enforcement Rapid Response Training (ALERRT) Center at Texas State University.

Popular training models now take a layered approach that prioritizes moving away from the threat rather than staying in place and if all else fails — fighting back.

After Sandy Hook, the FBI partnered with the ALERRT program to help train first responders for active-shooter situations. It’s been used to train more than 130,000 law enforcement officers since 2002.

“Pretty quickly, there were teachers who were asking their their cop spouses, ‘Hey, what should we be doing in this situation?'” Blair said. “So there was some informal training going on and we formalized that at least a decade ago.”

ALERRT, like other popular models including ALICE and the FBI’s Run Hide Fight, emphasizes avoiding the shooter, denying them access and acting in self-defense:

• Avoid — Pay attention to your surroundings. Have an exit plan. Move away from the source of the threat.
• Deny — If getting away from the threat isn’t an option, keep a distance between yourself and the source, create barriers, remain quiet and out of sight.
• Defend — If you can’t avoid the assailant or deny them access, defend yourself. Be aggressive and committed to your actions.

In the past, some districts have used so-called live crisis drills involving real weapons, actors or fake blood.

Texas passed a law last year that allows for allows simulations like those to be included as part of schools’ active threat drills. The American Academy of Pediatrics has warned against such drills for the potential emotional distress they can cause in children.

That’s one of the reasons Kim Anderson, executive director of the National Education Association, said she emphasizes evacuation and safety over more controversial simulations.

“They result in many students reliving forms of trauma so the active shooter part of the planning is something that is cause for concern for us,” Anderson said. “These kinds of things should be designed, of course, at the local level but we do believe that safety and evacuation plans are absolutely necessary and unfortunately (have) become all too common.”

Today, the implementation varies by scenario and its practice isn’t always called an active shooter drill.

In Purich’s preschool class, they practiced “zig-zag running” on the playground and rehearsed what they would do if the Big Bad Wolf entered the building. Students were encouraged during the drills to grab objects to throw at the nursery rhyme villain in case he got into the classroom.

Her second graders still don’t say the word “shooter” during drills, but the students know, Purich said.

The day after the Uvalde shooting, she knew she needed to broach the topic with her students. Not wanting to share details to children who didn’t already know, she asked for a show of hands: who knew what happened yesterday?

More than half the class raised their hands. Some were scared, sad or confused. Some cried.

“It’s something really hard for them to process, especially as 7- and 8-year-olds,” Purich said.

Her second grade class found one way. Purich’s students chose to make a vigil of hand-colored Texas flags and uplifting messages in memory of the 19 children and two teachers killed in Uvalde.

It’s that kind of empathy from children that fuels Purich’s love for teaching, but it pains her to know that shootings are something she and her students have to consider.

“I feel like I just have to accept it, sadly, to do what I love,” Purich said.