Senior Abigail Thompson was in a nearby classroom and heard the commotion.
"And then it was like, 'ahhhh!'" she said.
Her younger brother, Ethan, was also nearby. He said his teacher walked into the hallway to find Bouche, a former student, with his hands in the air and the shotgun on the floor.
She coaxed Bouche into her classroom, where he took a seat.
"He unloaded all his ammo from, like, (the) bulletproof vest he was wearing," Ethan said. "He was talking about how he was abused as a child and how he just wanted to get away from his abusive parents so he just wanted to get inside police custody so he didn't have to be by them anymore."
In the interview, Bouche talked about the moments leading up to the shooting
“A girl passed right by me. I just didn't want to shoot or kill people, because at that point, the adrenaline, the excitement kind of just faded immediately,” he said.
The injured 17-year-old is expected to be in the hospital for several days, according to a social media post.
Bouche is being held without bond on several charges including terrorism, aggravated assault with a firearm and possession of a firearm on school property.