Students fill the hallways, heading to their next class. The short blast of a bell pierces Capital High School. Teachers rush to their assigned rooms and students hurry into the classroom nearest them, highlighting the sudden emptiness in the Southside school's corridors.

A short space of time passes, followed by a soft click as a computer system locks every classroom door. The doors will not open until the perceived danger has passed. In the classroom where I'm sitting, I watch a teacher drop a bolt into place that secures the door into the floor so a potential attacker can't get inside.

Later, I learn that students who linger too long in the hallways are taught to hide in other areas of the school.

Back in the classroom, the teacher switches off the lights and closes the blinds. Everyone in the school huddles in a closet or against a wall, out of sight of doors and windows.

That's the operative mission here, we're told: Don't get seen by a school shooter.

On this occasion, I found myself in the middle of a training exercise for about 45 minutes. But I didn't know it at the time.

Lockdown drills to practice for an active shooter have become a regular part of students' lives, experts say, after the seemingly constant stream of mass shootings across the country in churches, schools and even a Wal-Mart.

So have lockdowns for actual threats.

In Santa Fe alone, my recent experience at Capital—coupled with a pair of real lockdowns last Tuesday at Milagro Middle School and Santa Fe High School—show that the phenomenon and the fear it inspires have not spared the City Different.

Despite the efforts of Santa Fe Public Schools, some of the district's lockdown and active shooter protocols are not considered best practices by national experts who specialize in the psychology of students and faculty, SFR has found.

The ambiguity surrounding whether the exercises are real or simulated, along with other protocols, could actually be traumatizing students, especially at Capital, where the population of immigrants and others have already lived through horrors.

While faculty and staff are encouraged to let students know that a lockdown is just a drill, such notification is not required.

Students in New Mexico public schools can expect to hide in a dark classroom or elsewhere on campus at least twice each school year from now on.

That's because lawmakers this year passed legislation mandating that all schools conduct at least two active shooter drills annually. It's the first time in state history that active shooter drills have been specifically required.

The law, adopted in the spring without a single opposing vote, reduced the total number of required fire and other emergency drills from 12 to eight. But it allows school districts more flexibility for incorporating active shooter drills.

SFPS will conduct 11 safety drills this year, including four fire drills, one evacuation, a lockdown drill inside the classroom and two when the students are switching classes or at lunch or recess, according to SFPS security chief Mario Salbidrez, the former deputy chief of the Santa Fe Police Department.

Salbidrez recently rolled out the use of an app called the Rave Panic Button at Santa Fe, Capital and Early College Opportunities high schools. He plans to initiate its use at Milagro and Ortiz middle schools and Mandela International Magnet School as well. The app can be used to alert law enforcement of a danger to put schools into lockdown and let teachers know when a lockdown is just a drill.

The district's general safety plan is based on best-practice recommendations from national security experts, according to SFPS Superintendent Veronica Garcia. However, she says, the district relies on local police to dictate safety protocols at incidents to which they respond.

Relying only on law enforcement to decide what type of drill is the most effective is not always the wisest, says Melissa Reeves, a school psychologist and researcher for the last two decades, who has developed best practices for teaching active shooter lockdowns.

"Law enforcement is used to training with highly sensorial activities because that's part of what they do, same with the military," Reeves says. "That is not what we need to be doing in schools."

Regardless of whether there is a threat, the Santa Fe school district wants it to feel legitimate. For many students, and for myself when the drill trapped me on campus at Capital that day after a mentoring session for the school newspaper, it felt all too real.

How best to train students and teachers on what to do when there is a threat on campus remains the subject of some debate.

Based on SFR's first-person account, Reeves says some of Santa Fe district's protocols follow agreed-upon standards and some don't.

For example, Reeves does not endorse withholding from students that a lockdown is just a drill because it "incites more fear" and if a real shooter is on campus, students don't know whether to take the situation seriously.

Lockdowns have the potential to inflict trauma, especially on vulnerable populations common throughout SFPS—immigrant children and those with autism, she says.

"We don't light a fire in the hallway to practice fire drills [and] we don't put a child on a street corner and have someone grab them and kidnap them to teach stranger danger," Reeves tells SFR via phone.

In addition to the lockdown drill, district schools have upped their security measures over the last several years. Some school officials use the Violence Threat Assessment training, which Reeves teaches around the country, as well as more controlled access to the school, security officers on campus, and alarms and surveillance video systems.

Lockdowns in response to a real threat are becoming more common, too, even if the cause is not a shooter on campus.

In just the first week of school this year, four lockdowns occurred due to threats in neighborhoods near campuses, Garcia said in August.

Garcia estimates that the district locked schools down 15 to 20 times "at a minimum" last year in response to real threats, most from violence in surrounding areas off campus.

The week after the active shooter drill at Capital, three public schools across town locked down for what turned out to be a real response to a fake campus shooter threat called in by students.

As armed law enforcement officers paced outside the locked doors of Milagro Middle school, a parent tells SFR her daughter inside suffers from a diagnosed anxiety disorder and both real school shootings around the country and emergency drills have exacerbated her condition. The woman did not want her name published due to concerns that publicity would negatively impact her daughter.

SFR asked the district through newly appointed spokesman David Carl how many drills and actual lockdowns have occurred so far this school year, but district officials did not respond before press time.

At the beginning of the school year, SFPS released a 12-minute video called "Run, Hide, Fight" as a tool for informing children about active shooter drills. Garcia calls their film a response to parents' concerns that a widely circulated film of the same name was too graphic.

Reeves tells SFR she considers the national Run, Hide, Fight video "absolutely unnecessary and quite frankly traumatizing" for students.

The SFPS low-budget, sanitized production is a mix of local school officials, staged classroom discussions and reenactments of what should be done during a lockdown.

Parents received a notice that their children would see SFPS's toned down version of the video. The district allowed parents and principals to make the final call about which students would see the video.

The video is just one of the ways the district has ramped up preparedness and security measures in recent years.

In 2018, the school district invested in a security system that checks the ID of people who want to enter the campus to make sure they are not registered sex offenders or anyone else who has been flagged as dangerous.

The schools also have check-in kiosks to track school visitors and make sure they can't enter the school unseen, as well as programmable locks on doors.

Garcia says behavioral and mental services remain the most important tools the district has for protecting schools from a threat that might come from a student.

"That's where threat assessments, that's where anti-bullying, and counselling services become very important," she says in August, "because many of these shootings took place by kids who have been bullied."

For Reeves and her colleagues, making sure that faculty and staff are staying connected to students is the most important step in preventing crises.

"Relationships and connectedness is our number one prevention and mitigation tool," Reeves says. "What we know is good crisis intervention helps to mitigate traumatic impacts. Our goal is that [students and teachers] don't have lifelong trauma implications. We're really trying to get in there and train school districts on that."

Leah Cantor contributed reporting.