Columbine, Now Aurora: Students Continue Lockdown Practice People light candles at a memorial for the victims in the shooting near Century 16 movie theater in Aurora, Colo., Sunday, July 22, 2012. James Eagen Holmes has been charged in the shooting at the Aurora theater early Friday that killed twelve people and injured more than 50. The audience at that midnight screening of The Dark Knight Rises was so young that 10 of the 12 Aurora, Colo., theater-shooting fatalities would have grown up in the post-Columbine era. Since that horrific school shooting, students in Colorado and elsewhere in the country have been practicing bunching together on the floor in corners of classrooms on a moment's notice, sometimes taping vents, always closing window blinds, locking doors and remaining silent. No one in that theater, I'm sure, expected to call on their training. Being in school is different. As a Jefferson County substitute teacher, I occasionally supervise these practice lockdowns. No matter what strange classroom you report to, the teacher's lesson plans and class roster are accompanied by a folder of instructions for a lockdown. PHOTOS: Batman Movie-Theater Shooting in Aurora, Colorado My first was at a feeder elementary school for Columbine High School. It was not a dry run - something threatening had been written on a schoolyard bench. I was in a first-grade classroom. Without unduly alarming the children, the blinds had to be closed, the doors locked from within and the lights turned off. I'd never taught a day in my life, and suddenly there was a classroom of solemn children, a couple of them whimpering and another child totally silent as tears ran down his face. Every now and then, a voice on the intercom would talk about the alert. When a key clicked in the doorknob and the children's regular teacher softly entered the classroom, I said a silent prayer of gratitude. My son doesn't remember the Columbine shooting being announced in his third-grade classroom. But he does remember that it was his friend's birthday and that somehow the teacher forgot to have everyone sing "Happy Birthday" and pass out cupcakes. When his school reopened two days later, the children sat on the floor in a circle around the teacher, who read the school district's script saying a terrible thing had happened and that the students should talk to their parents. My son remembers things changing after that. "Everybody became very, very cautious," he says. MORE: After Aurora, Lessons from Columbine Despite precautions, violence continued. Six years ago, a gunman got into Platte Valley High School - about an hour's drive from Aurora. He took several girls hostage and murdered one. Neighboring schools escalated their drills. Two years ago, a shooter injured two kids outside a Jeffco middle school before being tackled and taken down by a heroic teacher. Police and sheriff cars are commonplace outside many schools, and this past year I subbed at a suburban elementary school with a full-time armed police officer roaming the halls. As a substitute, I no longer find the lockdowns daunting, but they're always sobering. If you have an unruly group of high school seniors in a science class and there's a practice lockdown, you are astounded by how quickly and quietly the students sit down in the furthest corner from the doors and windows and remain silent - yes, seniors can be quiet! - for 15 to 30 minutes. The halls of huge high schools become deathly silent. Administrators prowl, rattling door handles and listening for voices. These practice lockdowns - not just in Colorado but across the U.S. - are so routine that you almost forget that the young people sitting on the floor are practicing how to react when faced with the possibility of death. The thought always occurs: They're sitting ducks. From the 1950s to the 1980s, there were several generations of duck-and-coverers. We were taught how to protect ourselves from an unexpected nuclear attack by a foreign power. The enemy was beyond our shores, half a world away. I don't remember any expectation that the enemy would walk up the sidewalk and through our school doors. There isn't much protective technique the practice lockdowners can take into a movie theater or shopping mall when a madman is intent upon demonic destruction. But it's worth noting that there are now two practice-lockdown generations - the 1999 Columbine High School kids having grown up to have school-age children of their own - and they are unfortunately learning to anticipate attacks by people whose crazy ideas were made in America and who are armed by their fellow countrymen.