Back in history class after the safety assembly, the students asked Mr. Duncan if he would take a bullet for them.

“No,” Mr. Duncan said immediately. “You wouldn’t expect me to, would you?”

They would, and they told him so. They were teenagers.

“You wouldn’t protect us?” asked Holly Manders from center of the first row. “If somebody came in here shooting? Actually shooting? Isn’t that your job?”

“Mr. Duncan,” said James Donaldson, raising his hand at the same time as his voice. “Didn’t you have to swear an oath or something? As a government employee?”

“But you’re old,” William Duval reasoned. “Not old. I mean, older. No offense, but we’ve got our whole lives in front of us. And you don’t have any kids, right?”

An awkward moment passed as everyone in the room considered the consequences. Mr. Duncan thought about the importance of critical thinking as a twenty-first century skill.

“Okay,” he told them, breaking the silence. “Let’s get back to communism.”

But on his drive home Duncan couldn’t stop thinking critically about it. Privileged bastards—he would die for them? He pictured the door to his room opening and a stone-faced boy in fatigues firing an assault weapon. He saw himself diving for cover among the tangle of student and chair legs, rolling on the floor and pulling a desk in front of his face and chest. Then playing dead. Who would blame him?

Well, they would. He actually liked his students, privileged bastards that most of them were. They couldn’t help where and how they were raised. Despite the privilege, they were basically good people. Most did their work. They participated in class and laughed at his jokes. In the hallway he heard as many kind words as he did sneers and sarcasm. And they were right—though he had a brother and a sister, and his parents were alive, he had no children and no wife. He was thirty-three.

That got Duncan thinking about Chad Ramsey, the young history teacher in his department. What would Chad Ramsey do if a cold-blooded killer barged into his classroom? Duncan pictured Ramsey diving in front of the gunman like a soccer goalie, stretched horizontally with his arms above his head, his students wide-eyed and gape-mouthed, smoke rising from the rifle barrel and staccato blasts echoing off the cinder block. Chad Ramsey, whom the students loved. He was smart and handsome and cool. He coached golf and basketball. He was given all the sections of Advanced Placement European History in his third year. The bullets would probably bounce off his chest.

A few weeks later, the administration and local authorities held a Code Red drill. An active shooter, played by one of the police officers, roamed the building. The students were told to take the drill seriously, though obviously they should not follow the protocol of Run, Hide, and Attack if the simulated shooter came into their classroom. Actually, it wasn’t clear what they were supposed to do.

Duncan thought there was something absurd and sick about staging such a charade. He hoped the shooter wouldn’t pick his room, but he was not surprised when the door flew open and a middle-aged man dressed in a black golf shirt and orange vest marked POLICE walked in, pointed a yardstick at them, and shouted, “Bang! Bang!”

There was no place for the students to run or hide, and instead of attacking, many of them laughed nervously. Duncan thought Holly Manders was about to cry.

“Okay,” said the cop, now out of character. “This is just a simulation to give you an idea of what it would be like with a real shooter in the room. There’s no running or hiding in the classroom, so if it were a genuine threat, you would have to attack.”

James Donaldson said from the back, “I was going to, but you probably would have arrested me.”

A few others laughed, easing the tension. Then the cop looked at Duncan, who was standing still in front of the whiteboard.

“And what should you do?” the cop quizzed him. “I mean, it’s not like you can dive like a soccer goalie in front of somebody who’s firing a weapon.”

Duncan didn’t respond.

“Attack,” the cop told him and left the room.

That was in September. The real shooter didn’t appear until May, and it was nothing like the simulation.

Duncan was washing his hands at a sink in the boys’ bathroom that he used every day during his planning period. He assumed he was alone until he heard a noise, something between crying and throat-clearing, from one of the stalls. He looked down at the closed door and saw the white tips of sneakers.

“You okay in there?” Duncan asked.

The noise stopped.

“You need anything?” he asked.

The sneakers moved a little.

“Hey,” he said, tapping his knuckles on the stall door. Not surprisingly, the door started to swing open—the latches were uniformly broken. Then it quickly slammed shut. He pictured the kid’s hand holding it there from the inside.

“Listen,” Duncan said. “If you don’t say something, I’ll have to go to the office and get an administrator. You sure you’re okay?”

For a few seconds, nothing happened. Then the door slowly opened and sitting on the seat was a boy Duncan had never seen before holding a gun in his mouth. He was moaning, or maybe it was humming, and rocking front to back.

When Duncan told the story, even for the first time to his principal before the police arrived, he knew he wasn’t being completely accurate. How could he know what his exact thoughts were? How many thoughts sped through his brain in those frantic, frozen seconds?

He knew that he must have considered Run and Hide. He knew that he probably considered Attack, but that was clearly out of the question, not with the gun in the boy’s mouth.

He knew he couldn’t move.

The boy rocked on.

The only sure thought that Duncan remembered from those few seconds was shocking. He thought about Chad Ramsey. He thought that whatever he did at this moment would forever be held up against Chad Ramsey and what the students and the administration assumed Chad Ramsey would do in the same situation.

Duncan never told anyone he had that thought. He did not tell the principal or the police. He did not tell his future wife during their courtship or in their forty-three-year marriage. He did not tell their two children and of course he did not tell their five grandchildren. He did not tell his sister, who died two years before he did.

He never told anyone that he had been thinking about Chad Ramsey.

He told them only what he saw—the boy leaning his head back and removing the gun from his mouth, then his own hand reaching out.