Biondi said she was in math class when she heard banging in the hallway.

“One of my teachers went out to see what it was,” she said. “He peeked his head out, and, as he was shutting the door, he got shot.”

She said it was initially tough to grasp what was going on.

“Once we all realized what happened, we ran to the back of the classroom, and we were all just sitting there,” she said. “Once my teacher yelled ‘help,’ my other teacher came running up to him and was grabbing rags and stuff to put pressure on the wound.”

Biondi said her teacher was able to shut the door as he was falling down after getting shot.

11Alive’s Molly Oak asked the 15-year-old if she thought her teacher saved their lives that day.

“Yes, I’m very grateful he shut that door,” she said.

She said he was a hero.

“(The shooter) might have came in,” she said, had her teacher not closed the door. “And I don’t want to think about that.”

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Biondi said they continued to hear more shots.

“So my teacher had to turn off the light. Once the police finally got there, we couldn’t leave the classroom because he was right in front of the door,” she said, as she remembered having to walk past her math teacher to get out. “And I just – I didn’t want to see that.”

She said when they were outside the classroom, they all had to put their hands up.

“We had to walk through the J Hall that had all the gunpowder and the bullets, and they told us to keep our heads up so we couldn’t see anything,” she described. “And, once we got out, it just didn’t feel real.”

Biondi said she is still processing what happened inside the school. She said she wants to go back eventually but said she is not sure if she’ll ever be able to walk down that hallway or sit in that classroom again.