Zach Petkewicz is one of the heroes, but when the shooting started, his first reaction was fear.
"I crouched down like everybody else," he told Matt Lauer on TODAY. "I got behind the teacher’s podium. Initially it was just fear."
But the gunshots and screams coming through the walls of his Norris Hall classroom didn’t go away. Petkewicz was "just hearing gunshots — eventually, the gunshots got closer."
Petkewicz looked at the classroom door. It struck him that "There’s nothing stopping him from coming in here. We were just sitting ducks."
Galvanized to action, Petkewicz grabbed a table and with his classmates shoved it against the door. Students stood at each end of the table holding it to the cinderblock walls around the door frame.
The shooter, Cho Seung Hui, his bloody work done in the classroom next door, "tried the door handle" Petkewicz said. Finding the door blocked, he threw his shoulder against it, forcing it open six inches.
Petkewicz and his fellow students pushed back as Cho emptied a clip through the door. They heard him reload, but "he didn’t try to get back in the second time." Instead, the killer moved down the hall for easier game.
Lauer asked if he could have predicted before the shooting how he would have reacted. The young hero, whose first reaction had been paralyzing fear, said that’s not possible for anyone.
"There’s no way of telling what I would have done until you’re put in that situation," he said. Having been there, he now has an idea of what moved him to action:
"I think it was a mixture of fear and adrenaline. And the will to survive."