That was the point of the school safety plan , lockdown drills and gunshot wound tutorials the 26-year-old choir teacher and other staff at the Santa Clarita school had become familiar with over time.

"Because I had the training, my instincts were good," said Holt, a teacher since January. "If I hadn't had that training, I don't know that I would have walked myself through what I truly had done in that situation. It probably made a big difference."

And not. Grace Anne Muehlberger, 15, and Dominic Blackwell, 14, died from their wounds. Three other teens were wounded. The gunman, identified as Nathaniel Berhow, died at the hospital after using the last bullet on himself on his 16th birthday

Grace Anne Muehlberger, 15, died of gunshot wounds from the shooting at Saugus High School.

"The training helped save some lives, but it didn't prevent the incident from happening," Holt said.

Los Angeles County Sheriff Alex Villanueva praised the thousands of students and staff who knew what do when gunfire erupted Thursday morning. They ran to safety or hid . They covered windows, barricaded doors and cared for victims.

"Kudos to all of them for a job well done and, hopefully, that's a job we never have to do again," Villanueva said.

The sheriff said Saugus High School had an active shooter drill a few weeks ago. Holt believes it was actually an earthquake drill. A lockdown drill was scheduled for next month, she said. Both agreed students and staff did as they were trained.

The 'Safe School Plan' and a familiar scenario

The lockdown protocol in the 245-page Saugus High "Safe School Plan" stresses that teachers ensure all their students are accounted for. All doors must be secured. Students are to be moved away from windows and doors. They should take cover under desks or tables. Teachers should position themselves between the students and doors.

A "Critical Incident Response Plan" worked out with the sheriff's department refers to the 1999 Columbine High School massacre of 13 people.

Photos: Yvonne Pane, Danielle Pane, Anh-Thi Ta and Ha Trinh pray while holding candles at a vigil in Santa Clarita on Sunday, November 17. More than 10,000 mourners gathered at the vigil at Central Park in Santa Clarita, the Los Angeles Sheriff's Department said. Hide Caption 1 of 11 Photos: Mourners gather at the vigil on November 17. Hide Caption 2 of 11 Photos: Students are comforted as they wait to be reunited with their parents on Thursday, November 14, following a shooting at Saugus High School in Santa Clarita, California. Hide Caption 3 of 11 Photos: Students and others wait outside a reunification center on November 14 in Santa Clarita. Hide Caption 4 of 11 Photos: Marco Reynoso, right, hugs his son, 11th-grader Dylan Reynoso, after reuniting at a park near Saugus High School. Hide Caption 5 of 11 Photos: People are led out of Saugus High School after reports of the shooting. Hide Caption 6 of 11 Photos: Hannah Schooping-Gutierrez, center, a student at Saugus High School, is comforted by her boyfriend, Declan Sheridan, a student at nearby Valencia High School, during a vigil at Central Park in Santa Clarita. Hide Caption 7 of 11 Photos: Parents wait for children to be released at nearby Highlands Elementary following the shooting that put area schools on lockdown. Hide Caption 8 of 11 Photos: First responders' vehicles line Centurion Way outside Saugus High School on November 14. Hide Caption 9 of 11 Photos: A father hugs his daughter after being reunited at a park near Saugus High School. Hide Caption 10 of 11 Photos: People affected by the Saugus High School shooting leave candles and flowers during a vigil at Central Park in Santa Clarita. Hide Caption 11 of 11

"Once inside (gym, office, library, classroom), lock and/or barricade yourself and others inside," the Saugus High School plan advises staff.

"Use furniture to surround the group with everyone assuming a prone position on the floor away from doors/windows. Once in place...No one leaves! No one enters!"

"We never called them active shooter drills," Holt said. "At teacher training, maybe we did active shooter training but with the kids, it was just lockdown. Kids would just run to the classroom. You closed the door. You locked it. You turned off the lights. I'm a new teacher so I only had one time that I practiced that. I think they do it every semester."

Holt said three terrified students — one of them unaware that she had been shot — barged into the classroom where 30 choir students were listening to a recording of a recent performance at a jazz festival.

"Especially when the kids ran in, I had played the scenario in my head a bunch of times," she said.

They locked and used rolling mirrors, a grand piano and chairs to barricade the doors to her classroom.

One girl suddenly realized she had been shot, Holt said.

"We have a gunshot wound kit in my classroom that I really thought I was never going to use," the teacher remembered.

Women embrace in Central Park after a shooting at Saugus High School on November 14, 2019.

She momentarily left the office to retrieve the kit from a shelf in the classroom.

"We had watched a tutorial on how to use that in one of our staff meetings," she said. "So, I did the best I could remembering how to ... (use) the gunshot wound kit."

The girl discovered a second gunshot wound as Holt wrapped up the first.

"I'm going to be home-schooled after this," the girl joked.

"You're going to make it," the choir teacher said. "We're going to be on the news today."

Holt later saw a photo of the wounded student, the niece of another teacher, smiling as she recovered from surgery at a hospital.

Participants. First responders. Potential victims.

Holt and other staff took on many roles during the shooting. They were participants, first responders and potential victims.

"I had many jobs to do so I never had a moment to think that my life might be in danger," she said. "Whereas my kids were terrified. And I would have been terrified, too, if I had not had all these all these jobs."

A teacher should never have to be a paramedic, Holt said.

"I can only imagine if that student had not made it how I would be feeling and I should not have ... to feel like I needed to be trained like a paramedic to save someone's life," she said. "I'm there to teach and the kids are there to learn."

In the office with her students, Holt urged them to dim their phone screens and keep the ringers silent.

"I told them, 'I know it's going impossible to tell you to stay off your phone,'" she recalled. "I said the light has to be off, the sound has to be off. They kept quiet."

Threat assessments and text tips

The California school district has other contingencies : A threat assessment team that uses resources from the FBI, the US Secret Service and US Department of Education; a text-a-tip line for students to report suspicious activity; school resource officers and law enforcement partnerships.

But the motive for Thursday's violence remains a mystery.

"There's nothing really that stands out" about the shooter, Villanueva said.

"He wasn't a loner. Wasn't socially awkward. Was involved in student activities. Student athlete. This is kind of out of the blue, shocking pretty much everyone who knew him."

Investigators were looking into the shooter's social media and background, the sheriff said. There appears to be no connection between the him and the victims other than they were students.

Holt said labeling her a hero made her uncomfortable. Others at the school acted heroically.

"It's very fight or flight," she said. "I had zero thoughts cross my mind. I think anybody at all would do the same thing ... I feel a hero makes like a choice and I was just moving."