When shots were fired outside his high school Thursday morning, Eddie Mendoza, a 17-year-old senior, had been in the choir room practicing a new song.
"My teacher said, 'Get in the office, get in the office,'" Mendoza told BuzzFeed News. "We all ran into the small choir office, sitting there all quiet."
That's when a girl ran into the room, bleeding from two bullet wounds, he said.
"I heard someone say, 'I think I was shot,'" he said.
His teacher at Saugus High School in Santa Clarita, California, Kaitlin Holt, acted like a hero, Mendoza said. She ran to get a first aid kit and barricaded the door so students would be safe as they sat in the dark while she was briefly gone.
"She immediately jumped into action," Mendoza said.
When she returned, the teacher covered the girl's wounds and tried to control the bleeding.
Mendoza said it was "heartbreaking" seeing one of his own classmates bleeding from a gunshot wound — in a room where he'd been happily singing minutes earlier.
"She kept saying 'I want my mom,'" Mendoza said. "But she was strong, and we comforted her. She's a fighter."
It's unclear if the young woman died. Authorities said six students were shot: A 16-year-old girl and a 14-year-old boy were killed. A 14-year-old girl, a 15-year-old girl, and a 14-year-old boy were injured. The shooter, 16, shot himself in the head and died Friday afternoon while being treated at the hospital.
The young woman in the choir room "was talking; she was conscious," Mendoza said.
Other students in the room helped tend to the girl.
"One of my friends, she had to nurse one of the girls who got shot," Sona Tigranyan, a Saugus High senior, told BuzzFeed News.
While school shootings have become horrifically commonplace in the US, Mendoza said he "never in a million years" imagined one would happen in his own school.
"I feel so hopeless, I guess," he said. "It's happened multiple times, and it's frustrating for us to be added to the list of school shootings."
"It opened my eyes that nobody is safe," Mendoza said. "The world is very cruel."