Some people form mental pictures -- "brain movies" -- when we read.

I never watch television footage of heinous crimes. It’s too gruesome for me to bear. But I do read news reports obsessively, and the stories from America’s school shootings have imprinted indelible brain movies in my mind.

The events 11-year-old Miah Cerrillo described to CNN last week should be seared in our collective memory.

Miah was one of the fourth graders trapped in a classroom at Robb Elementary when a gunman rained gunfire on her peers and teachers, killing 21 of them. In order to survive, she placed her hands in the blood of her dead classmate, who was lying next to her. She smeared her friend’s blood on herself and played dead.

She managed to escape death at the hands of a teenager armed with an AR-15 rifle and hundreds of rounds of ammunition -- an 18-year-old too young to legally buy a beer, but able to purchase military-style assault weapons.

It hurts to think about what Miah must have experienced in those moments. Her class had been watching the Disney movie "Lilo and Stitch" before the nightmare began. Then, suddenly, she was watching her teachers and classmates murdered in front of her.

Spend a minute thinking about what this little girl endured just to survive. Think about the lifelong trauma she will carry inside her.

This kind of terror has unfolded in American schools over and over and over: More than 311,000 children in America have experienced gun violence in school since Columbine, according to a Washington Post database.

That’s more than the population of St. Louis.

Imagine how the worst moments of Miah’s young life were made even worse by feeling abandoned by those she thought would protect her.

She and a friend managed to get their slain teacher’s cellphone and dialed 911 -- exactly what we teach our children to do in an emergency.

“Please come ... we’re in trouble,” she told a dispatcher.

No one came.

Armed officers stood outside that door for more than 40 minutes while children were trapped inside with a madman wielding an AR-15.

A child called again, begging for help: “Please send the police.”

Miah started crying when she remembered hearing officers outside, saying to CNN she just didn’t understand why they didn’t come inside and rescue them.

I can hear the voice of a terrified child calling 911 again and again.

“Please send the police.”

We need to sit with that and hear those words in our children’s voices. What would we do to protect them?

The Uvalde Police Department and the Uvalde Independent School District police force are no longer cooperating with the Texas Department of Public Safety’s investigation into their delayed response during the massacre. The officers waited for around an hour outside the adjoining classrooms because a commander on the scene wrongly believed the suspect was "barricaded" and that no lives were at risk.

Police outside Robb Elementary even threatened to arrest parents trying to rush in to save their children. The Uvalde police department's version of events has changed several times.

But this wasn’t the first time we saw armed “good guys” waiting it out while children were murdered inside a school. The school resource officer in Parkland, Florida, stood outside Marjory Stoneman Douglas High School while 17 people were murdered inside by another teenager wielding an AR-15.

Do the chaos and terror of a mass shooting paralyze some "good guys" with guns? Does a survival instinct override the oath to serve and protect? Is it fear? Is it cowardice? Is it knowing that their weapon is no match for a semi-automatic rifle? And why do we expect teachers to be even braver and more heroic than these "good guys"?

The Texas Tribune reported that FBI analysis of 277 gun massacres between 2000 and 2018 found that “so-called 'good guys with guns' interrupted mass shootings 3.9% of the time.” By comparison, unarmed civilians interrupted them almost three times more often (11.9%).

Unarmed civilians like teachers, principals and children, who have all sacrificed themselves during school shootings to save other children.

As for the myth of the "good guy with a gun" stopping the bad guy?

Bury that for good.

I don’t feel numb to the massacre of children in American schools.

I feel a growing anguished disgust.

Last week, an 18-year-old man fatally shot at least 21 people at Robb Elementary School in Uvalde, Texas. It’s just the latest in a long series of uniquely American horror stories.

The reason each school shooting feels worse than the one preceding it is precisely because it keeps happening. We know how to make them less likely, but GOP politicians hold our children hostage.

The Republicans are now wholly owned by the National Rifle Association, which is owned by the gun manufacturers. They continue to deny evidence and common sense that improving gun safety laws would mean fewer such tragedies.

Their denial is deadly for America’s children.

Why should a disturbed 18-year-old be able to buy two AR-15 rifles and 375 rounds of ammunition -- enough to wipe out an entire school? Why is America the only country where this keeps happening? Why do we allow our children to be traumatized by intruder drills, never feeling safe at school, fearing classmates and teachers being gunned down?

Guns are now the leading cause of death for children and adolescents in America.

We are a sick country.

As I followed the reports of the events in Uvalde, I was struck by these observations and how the “debate” following these mass gun crimes often goes in the same circles.

Think about how gruesome this is: “The parents had to provide DNA samples because their children’s bodies had been mutilated beyond recognition,” wrote historian Kevin M. Kruse on Twitter.

What if Americans had to face the images of the brutalized victims of these mass shootings? How much longer would we tolerate the status quo?

Current and former teachers described the terror and trauma of intruder drills and the unthinkable scenarios they are forced to act out with the smallest children.

“What they don’t tell you is teachers are told in training that they have to lock out any of their students who are out of the classroom,” tweeted author and teacher Erin Hahn. “Even if they beg and bang on the door. Because there could be a shooter using them to access your classroom.”

That means if a kindergartner uses the bathroom and gets stuck in a hallway during an intruder drill -- or, the worst possible nightmare, an actual attack -- that 5-year-old would be crying and banging on his teacher’s door to be let inside, only to be left in the hall. Potentially with a killer.

Others pointed out how quickly the government is able to take action on behalf of powerful adults, but not vulnerable children.

“Ten days ago it took the Senate about twenty minutes to unanimously pass a bill extending security protection to the family members of Supreme Court justices when it looked like a house might be picketed,” noted Kieran Healy, a sociology professor at Duke.

Texas Republican Gov. Greg Abbott, who has signed dozens of bills making it easier to buy guns in Texas, was asked at a press conference about gun safety reforms. He pivoted, pointing fingers at the gun violence in Chicago.

Journalist Kelly Bauer tweeted in response: “(about) 60% of ‘crime guns’ taken in by Chi police are bought in other states where laws are more lenient” -- a point echoed by Illinois Gov. J.B. Pritzker.

So, what is the Republican response to school shootings? It’s often “put more cops in schools” or even “arm the teachers.”

“But guess what?” tweeted legal analyst and scholar Harry Litman. “There was an armed officer in Uvalde, and then two more arrived on the scene. They didn’t stop the killer, who was in the school for an hour before being killed.”

“Not one, not two, but three armed cops” failed to stop the Uvalde shooter, agreed writer Alex Thomas.

More than 90% of Americans support universal background checks for gun purchases.

“I personally own a closet full of guns. I also have a concealed carry permit. And I will ‘happily’ fill out more paperwork and have my background checked if it means little kids get to go home to their parents at night. The Senate needs to vote on HR 8 now @SenSchumer,” tweeted tech expert Zack Nelson.

Nelson was referring to the Bipartisan Background Checks Act of 2019, which expands background checks to private gun sales and gun shows. It passed the House in March 2021. All 50 Republican senators, plus Democrat Joe Manchin, are opposed to it in the Senate.

National Youth Poet Laureate Amanda Gorman succinctly captured what America has become: “The truth is, one nation under guns.”

Three years ago, a first-year student in my college writing class wrote a paper that struck me as a sad reflection on the American high school experience. They argued that high schools should limit the number of Advanced Placement classes a student is allowed to take each semester.

Even those students who'd been accepted into one of the best colleges in the country couldn't shake the memory of the intense pressure placed on high-achieving high schoolers -- so much so that they wished, in hindsight, that their opportunities had been limited.

Now that I've seen two of my own children and their friends go through the junior year gantlet, I recognize that paper as a plea for help. I remember my junior year -- in an oversized, competitive high school -- as rigorous and stressful. But my Gen X experience was markedly different from what today's teens are enduring.

For example, selective and highly selective colleges are far more difficult to gain admission to. The advice from college admissions and guidance counselors is to take the most academically rigorous course load possible. My writing student described having to pile on AP classes -- regardless of interest in the subject matter -- to maximize GPA and stand out among other applicants. There was no time or space in the school day to take an elective class simply to pursue an interest. Taking five or six college-level courses a semester translates to hours and hours of homework each night.

In 2018, the College Board reported that over the previous decade, the number of U.S. public high school graduates who took an AP exam during high school increased by 65%. Meanwhile, students in predominantly Black and Latino schools continue to lack the kind of access to AP classes offered to their peers in predominantly white schools.

This is partly why my student's paper was so striking: Those from the most elite backgrounds saw these increased AP opportunities as a burden.

Schoolwork is just one of the many responsibilities they juggle: By junior year, students are also expected to hold leadership positions in their extracurricular clubs and activities. Yet, even that isn't enough anymore. They also must create or implement some new, ambitious program to demonstrate their leadership abilities. For those who also play sports or an instrument, junior year is when competition and training intensify -- even more so for those who compete in time-intensive club sports. On top of this, they are supposed to prepare for and take high-stakes college entrance exams.

How did it become normal for 16-year-olds to work, practice, train and study from 7 a.m. to midnight every day? If adults had to put in 90 hours a week to meet the obligations piled on them, we would rightly call that exploitation. For many high schoolers, it's just part of the grind.

When we wonder why increasing numbers of teens and young adults are reporting higher levels of anxiety and depression, we ought to look at the culture we've created and at the schedules they are expected to manage during the same years when we had time to just hang out with friends.

An exceptionally motivated and bright high schooler confided to me that she feels she can't afford to waste a minute of her time.

"I have this mentality that I should be doing something at all times," she said. She signed up for five AP classes her junior year and leads several student and civic organizations. She frequently feels stressed, stretched too thin and overwhelmed. But she says that's how most of her peers feel, too. Even when students power through it, it reinforces the idea that they must live with unacceptable levels of stress to achieve "success."

That is also why my student's paper was so poignant. The writer wanted an authority figure -- school officials -- to step in and set a limit. Imagine the backlash there would be from parents at any school that tried this.

There's no one to save these students from themselves.