Students and teachers responded as trained when the fire alarm sounded, streaming out of the school and toward exits only to run into deadly gunfire.

Two boys with stolen guns took aim from a wooded hill, waiting for people to evacuate after one of the boys had triggered a false fire alarm. They killed four children and a teacher.

That was 20 years ago at Arkansas’ Westside Middle School, before active-shooter drills became part of the routine for schools across America.

Students today are taught to evacuate during fire alarms but lock down during school shootings. So there was confusion Wednesday when a fire alarm sounded – the second one that day – at a Florida high school as 19-year-old former student Nikolas Cruz unleashed a barrage of gunfire. Head for the exits or hunker down in classrooms?

GUNMAN PULLED FIRE ALARM?

As in many U.S. schools, students and teachers at the school had trained for both responses, just not at the same time. Seventeen teachers and students were gunned down.

Unconfirmed initial reports suggested that Cruz pulled the fire alarm himself, but authorities haven’t confirmed who set off the alarm in Parkland.

Emergency responders say there is no single accepted set of best practices for responding to active-shooter situations, and the protocols vary from district to district around the country.

That includes everything from consistent drills to strategies for teachers to fight back with baseball bats and soup cans if confronted by an armed intruder.

Safety experts say it’s unusual for schools to encounter situations where drills contribute to confusion or are exploited to inflict more harm, though they concede the reality of that possibility.

“We might be training the suspect in our drills,” said Mac Hardy, operations director from the National Association of School Resource Officers. “I mean, we understand that, we know that, but we have to also do the best we can in the situations we’re in to try to keep as many students as safe as possible.”

Drills should encourage people to think on their feet, said consultant Kenneth Trump of National School Safety and Security Services in Ohio. That might mean starting a drill when students are in hallways or lunchrooms instead of class, or telling a teacher in the midst of a drill to pretend a particular route is blocked, he said.

Various organizations offer guidance about dealing with an active shooter. The National Fire Protection Association is working on a proposed accredited standard for responders at the request of an Orlando-area fire chief who, after the 2016 Pulse nightclub shooting that killed 49, thought it was time to have some minimum criteria that communities and facilities could consider adopting for how to prepare for and respond to such events.

In the Westside Consolidated School District, where the 1998 shooting occurred, a given classroom won’t always use the same exit when the district does monthly fire drills required by the state.