Miami (AFP) - Shots ring out in a Miami school classroom.Inside, a dozen students, their clothing stained with what appears to be blood, desperately scream.
A security agent walks down the hall, more shots are heard -- and a young man is swiftly knocked down.
It's a terrifying scene -- but, thankfully, it is a simulation.The bullets are blanks, and the blood and wounds are fake, as are the screams and the guns carried by the dozens of police officers taking part.
The teenagers are volunteers helping police to fine tune their reaction to school shootings in the United States, once again under the spotlight after the disastrous law enforcement response to a deadly gun rampage at an elementary school in Uvalde, Texas in May.
There, law enforcement agents waited 73 minutes before finally engaging the shooter, who killed 21 people -- most of them young children.
The police response outraged Americans, especially after the release of surveillance footage showing officers waiting in the corridors of the elementary school as children and teachers lay dying behind the closed doors of the classrooms.
Legacy of Columbine
"Our rule is that the first officer on the scene confronts the shooter.Everything is done to save lives," said Major Carlos Fernandez of the Miami-Dade Schools Police Department.
It's a rule of thumb that has been in place for many police departments since two teenagers killed 13 people at a high school in Columbine, Colorado, in 1999.
There is no US federal guideline on the police response to school shootings.But before Columbine, the norm was for officers to wait for SWAT tactical units to intervene, Fernandez notes.
After, the priority became to stop the killing by rushing towards the gunfire and engaging the shooter as soon as possible, before helping the wounded -- which the officers in Uvalde failed to do.
During the simulation in the Miami suburb of Hialeah, the false suspect is taken out of action just three minutes after the first shots were fired.
The street swarms with police cars in front of the school, as agents run down hallways and check that bathrooms and classrooms are empty.
With everything under control, firefighters enter the building and take away four students with fake injuries.
In the past, medical teams waited outside schools -- but now police try to clear the facility as soon as possible so that they can enter quickly, Fernandez says.
'Lasting emotional and physical harm'
This simulation, in the middle of the summer vacation, is for police, not students; and the 30 teenagers covered in gory makeup and screaming themselves hoarse have chosen to be there.
But for the rest of the year, active shooter drills are required for public school students in at least 40 of the 50 US states.
And that, argue NGOs and trauma experts, may harm students more than it helps them -- particularly when the drills edge closer to realistic simulations like the one in Hialeah, with fake blood, wounded victims and guns.
Gun control advocacy group Everytown last year studied the social media conversations of students in 114 US schools, 90 days before and 90 days after active shooter drills.
They concluded that the drills are linked to increased depression, stress, anxiety and physiological health problems in children as young as five years old, while concerns about death also shot up.
There is "almost no research affirming the value" of such drills for preventing shootings or keeping children safe when one does occur, while the evidence "suggests that they are causing lasting emotional and physical harm to students, teachers, and the larger community," Everytown said.
Sandy Hook Promise, a nonprofit founded by some of those who lost loved ones in the shooting at Sandy Hook elementary school in Newtown, Connecticut in 2012, draws a line between safety drills such as lockdowns -- which it says are "scary enough" -- and "live-action simulations of fatal shootings."
It warns of a "dangerous trend" towards simulations in schools that make drills "more traumatizing than helpful."
But when the drills are for police rather than students, it is important that the exercises are realistic and that children take part, argues Miami-Dade Schools Police Chief Edwin Lopez.
"Our goal is to unnerve the officers as much as possible.And that involves students screaming, fire alarms going off, smoke, sound or actual gunshots," he explains after the Hialeah drill.
"And it's critical that children make a valuable contribution to our officers.Many of them give law enforcement the information they need on a daily basis to mitigate and prevent" shootings, he adds.
