What should you do if you're caught in an 'active shooter' situation? That question has received a lot of attention in the wake of the Paris terrorist attacks this month that killed 130 people.
Prominent security officials like New York City Police Commissioner Bill Bratton have said organizations like his are undergoing a 'very significant change' in how they approach such situations, trying to more actively fight such shooters instead of negotiating.
This type of thinking, unfortunately, is nothing new for one group of organizations that has had more than its fair share of 'active shooter' scenarios: public schools.
In Missouri, state law now requires that schools put their staffs through 'active shooter' drills. In fact, in a former career, I went through a type of training in Independence that has garnered some controversy for its realistic methods.
It is something that since the Columbine tragedy in 1999, schools have been forced to think about. School shooters, of course, have had very different motivations than the Paris attackers but experts say schools may have something to teach the rest of society now that this topic has once again come to the fore.
"It's situationally driven," says Paul Fennewald, Director of the Missouri Center for Educational Safety. "You don't say automatically now to just lockdown in a classroom. Going to hide somewhere or trying to get out may be better options."
Fennewald says schools are "ahead of the curve" in thinking about dealing with active shooters. His organization, under the umbrella of the Missouri School Board Association, tries to educate school districts about the latest training methods.
"We saw in Columbine, staff members there said they felt like they didn't have the option of leaving. We've gone beyond that now as a state and as a country," Fennewald says.
In contrast, he says, many businesses have not spent the time and resources training their workers in such a way. School leaders have been forced to think about it more.
"Every school superintendent or administrator, this is in the back of their mind. To do their due diligence, they are asking themselves: 'have we ensured if it were to happen here we have had the training, the drills? Can we lock our doors and secure our classrooms?'"
Some schools (not in Missouri) have gone as far as to have students don bloody makeup and lay around the school as if they were victims to create a more realistic environment during active shooter training.
Schools in Missouri are currently applying for school safety project grants through the Missouri School Board Association, that could be used to fund more training and the purchase of things like security cameras.
Fennewald says the "majority" of schools in Missouri have "high-quality" school safety plans, and says his group is working to make sure those that don't get caught up to speed.
Unfortunately, after Paris, they probably won't be the only ones interested in that.
CORRECTION: An earlier version of this story incorrectly stated that the shooting at Columbine High School occurred in 1998. It happened in 1999.
Kyle Palmer is morning newscaster and a reporter for KCUR 89.3. You can find him on Twitter, @kcurKyle.