A choir teacher at the Southern California high school where a teen shooter opened fire on his classmates recalled the moment when she, along with “a really brave freshman,” helped a girl who had been wounded.

Katie Holt hunkered down in her classroom with 30 to 40 students, hiding from 16-year-old Nathaniel Berhow, who allegedly fired off a .45-caliber semi-automatic pistol at Saugus High School in Santa Clarita just before classes began Thursday, killing two and wounding at least three, NBC News reported.

One of the students who ran into the classroom told Holt she believed she had been shot.

“I investigated with my phone flashlight, and yes, she had been shot,” Holt told the network.

Holt left the locked office during the chaotic scene to retrieve her first aid bag and a gunshot wound kit — which have become increasingly common on campuses nationwide.

“She was shot in her side, and then she told me she thought she had been shot, as well, in her arm,” Holt told the station. “I looked, and she had been shot in her shoulder, as well — but I only had one gunshot wound kit.”

She used what she had to treat the girl’s shoulder wound, as a “really brave freshman” named Tyler applied pressure while she tended to the other wound, according to the report.

Then Holt and Tyler called the police, she said.

The wounded girl — who is reportedly out of surgery and recovering well — was “really strong” in those tense moments Thursday morning, Holt told NBC.

“She was even joking with me,” Holt recalled. “She said, ‘I’m going to be home-schooled after this.’”

“All my students were really strong, because they were — obviously, they’ll never be the same,” Holt added. “I don’t think I should have had to process this. I don’t think my kids, especially, should have to process this.”

Holt said she hopes “something can be done” to stop future school shootings, “because I think that a really big change needs to happen.”

“I held a bleeding child today in my classroom, in my music classroom,” she said.

Student Malena Peters told the outlet that she and her friends had just been talking about their course of action if a school shooting were to happen.

“I never thought it would actually happen, you know?” she said.

Former California Congresswoman Katie Hill, an alumna of Saugus High School — who on Thursday tweeted her horror as the shooting unfolded — told NBC that “parents don’t expect this.”

“But I think it’s becoming more and more the norm,” she continued. “And it’s horrifying for us.”

“Unfortunately, we’re at a point where, as a public … we talked all the time about how this is one of the worst nightmares to be happening in your community,” she said. “Not only for, of course, the tragedy, but because there’s so little that you can say when you go back about what we can do.”

Hill, who represented Santa Clarita and surrounding communities, recently stepped down from her role as a congresswoman after she became embroiled in a “throuple” scandal and was caught having a relationship with one of her subordinates.