The gunshots came from upstairs, pop-pop-pop, and Lindsay Aikman’s heart thumped faster and faster. The school’s public address system announced an active shooter.

The teacher dashed for the nearest hiding place – the boys’ bathroom. She regretted it when the automated lights flicked on. Her thoughts raced: “Should I have gone to the girls’ bathroom? Farther away. Library? Too open. A classroom? Sitting duck.”

As a tense voice over the loudspeaker described the shooter’s movements, Aikman wondered to herself: “Why is it an office assistant’s responsibility to deliver life-or-death information?”

The bathroom stank of urine. She was wearing a smart outfit for a meeting. She crouched on the toilet, keeping her feet off the floor in an effort to preserve both her shoes and her hiding place.

Why won’t the lights turn off?

Silence. Then, again, pop-pop-pop. Footsteps – how distant?

Aikman wept in dread and frustration. More head spinning.

“Man, I’m so stupid for going into the bathroom, I should have just gone outside … I’ve got kids to raise, I hope they’re safe at their school. Why am I doing this job? Isn’t there a different way to handle this issue? I don’t know how to explain this to my husband.”

Then it was over. It was “just” a drill. Aikman splashed her face with cold water and went back to work. Unlike at Marjory Stoneman Douglas high school in Parkland, Florida, last month, there had been no shooter and not even any kids to deal with. It was a teachers-only drill at her high school in Illinois.

Versions of this ritual are now stitched into the fabric of the American educational system, from kindergarten to university. But teachers are starting to question it.

“The drills are hard emotionally for some kids. Certainly they’re difficult for me as a teacher. There’s a little piece of heartbreak in every drill,” Corey Thornblad, a history teacher in Virginia, told the Guardian.

“Every time something like this happens – Virginia Tech, Sandy Hook, Parkland – and then we do a drill you can see it in their faces,” she said of her students.

A chime then a code over the intercom system lets teachers at her school know if the lockdown is a drill or a real emergency. “It’s eerie … you’re all business but it’s a little bit haunting,” she said.

Corey Thornblad: ‘There’s a little piece of heartbreak in every drill.’ Photograph: None

Classroom doors are locked at all times in her school. During a drill, Thornblad opens the door and quickly looks for any children in the hallway. Once the door is locked again and, with the blinds down and computers turned off and her students, aged 12 to 14, huddled on the floor in the dimness, she is not allowed to reopen it. Even if a child is begging to come in.

At the Parkland massacre, the school fire alarm was activated by the suspect, which brought students pouring into the corridors, causing enormous confusion when the shooting began. Teachers told the Guardian last weekend of their excruciating decisions whether to follow protocols adapted since 2012’s Sandy Hook massacre and keep doors closed no matter what. Or open them to let in kids who were defenseless in the corridors. Some who followed orders to keep doors closed have since been called cowards by children who were shut out.

Aikman teaches English, social justice and college readiness at a large public high school. “This is a very heavy time to be an American school teacher,” she said.

Staff and students are jumpy. “Whatever classroom I’m in I’m looking at how to exit in an emergency. That’s how we’re thinking now as teachers. What I could use to break a window, what I would use to barricade a door, how I would keep people quiet.”

Aikman said a colleague gets texts at work from her husband, checking to make sure she is OK, saying things like: “I just had a weird feeling, I wondered if today was the day.”

She spends extra time hugging her own kids goodbye in the mornings, wondering: “is this the day I’ll end up having to remember everything about this morning?” Teachers report having panic attacks during drills, taking anxiety pills beforehand. Aikman said a married couple at her school plan to flee from different exits so at least one will survive to raise their children. Drills for tiny children at some schools are presented as a game called “hibernation” where they take a stuffed animal into the bathroom or closet and hide.

One teacher tweeted, after a recent drill, about watching her 10-year-old students glancing anxiously at her, at the floor or at the door of the closet where the whole class was crammed, pretending a shooter was outside. After the exercise, she recalled: “10-year-old eyes darted to see if peers were equally frightened, 10-year-old hands shook slightly.” She handed out good behavior points, praised the children for staying calm, told them they were safe. “The watery smiles and minuscule nods I was given were wrenching agony. They smelled the lie. They are 10, they know closet doors won’t save them.” The teacher then went and cried in the bathroom. She later deleted the tweets and the Guardian is withholding her identity.

Meanwhile, during an exercise for teachers in Massachusetts, 10 staff were told to line up in the corner of a room. A man in a hood went one by one, pointing a gun at their heads and saying “bang”.

It was too much for participant Kathleen Moylan, who walked out, sobbing. “I was too upset to continue with the training,” said the history teacher at the high school in Worcester. “How is this something that is going to help us?” she asked in an interview with the Worcester Telegram.

She had once taught Dan O’Neil, who was 22 when he was among the 32 people killed in the mass shooting at Virginia Tech in 2007.

“Some of this training really does feel like rearranging deckchairs on the Titanic if we don’t want to deal as a country with the larger issue of assault weapons and background checks and all of that. It feels like we’re avoiding the major issue,” Moylan told the Guardian.

Thornblad, a member of the Moms Demand Action for Gun Sense in America advocacy group, is, however, encouraged by the youth movement ignited by Parkland. Massive crowds inspired by the survivors turned activists took part in the March for Our Lives last weekend.

Thornblad reminded her students that they would be able to vote one day.

“You can be part of the solution,” she told them. “I wanted them not to feel hopeless.”