People yelled at him amid the chaos but he didn't hear. He experienced "a tunnel vision of concentration."
While two teachers and three students were injured when the glass shattered in the 2001 attack on Granite Hills High School, Agundez confronted the assailant and wounded him before he could get inside the school and use his second weapon, a handgun.
The National Rifle Association's response to a Connecticut school massacre envisions, in part, having trained, armed volunteers in every school in America. But Agundez, school safety experts and school board members say there's a huge difference between a trained law enforcement officer who becomes part of the school family — and a guard with a gun.
The NRA's proposal has sparked a debate across the country as gun control rises once again as a national issue. President Barack Obama promised to present a plan in January to confront gun violence in the aftermath of the killing of 20 Sandy Hook Elementary School students and six teachers in Newtown, Conn.
Agundez said what happened before the shooting in the San Diego County school should frame the debate over the NRA's proposal.
With a shooting at another county school just weeks before, Agundez had trained the staff in how to lock down the school, assigned evacuation points, instructed teachers to lock doors, close curtains and turn off the lights. He even told them computers should be used where possible to communicate, to lessen the chaos.
And his training? A former SWAT team member, Agundez' preparation placed him in simulated stressful situations and taught him to evade a shooter's bullets. And the kids in the school knew to follow his advice because they knew him. He spoke in their classrooms and counseled them when they came to him with problems.
In the wake of the Sandy Hook massacre, school boards, administrators, teachers and parents are reviewing their security measures.
School security officers can range from the best-trained police officers to unarmed private guards. Some big-city districts with gang problems and crime formed their own police agencies years ago. Others, after the murder of 13 people at Columbine High School in 1999, started joint agreements with local police departments to have officers assigned to schools — even though that was no guarantee of preventing violence. A trained police officer at Columbine confronted one of two shooters but couldn't prevent the death of 13 people.
"Our association would be uncomfortable with volunteers," said Mo Canady, executive director of the National Association of School Resource Officers — whose members are mostly trained law enforcement officers who "become part of the school family.'"
Canady questioned how police officers responding to reports of a shooter would know whether the person with a gun is a volunteer or the assailant.
Former Rep. Asa Hutchinson, who also was a top Homeland Security official and will head the NRA effort, said the program will have two key elements.
One is a model security plan "based on the latest, most up-to-date technical information from the foremost experts in their fields." Each school could tweak the plan to its own circumstances, and "armed, trained, qualified school security personnel will be but one element."
The second element may prove the more controversial because, to avoid massive funding for local authorities, it would use volunteers. Hutchinson said in his home state of Arkansas, his son was a volunteer with a local group "Watchdog Dads," who volunteered at schools to patrol playgrounds and provide added security.
He said retired police officers, former members of the military or rescue personnel would be among those likely to volunteer.
There's even debate over whether anyone should have a gun in a school, even a trained law enforcement officer.
"In general teachers don't want guns in schools period," said Dennis Van Roekel, president of the National Education Association, one of the two large unions representing teachers. He added that one size does not fit all districts and said the union has supported schools that wanted a trained officer. Most teachers, he said, do not want to be armed themselves.
"It's a school. It's not a place where guns should be," he commented.
The security situation around the country is mixed.
—Maricopa County, Ariz., Sheriff Joe Arpaio says he has the authority to mobilize private citizens to fight crime and plans to post armed private posse members around the perimeter of schools. He said he hasn't spoken to specific school districts and doesn't plan to have the citizen posse members inside the buildings.
—The Snohomish School District north of Seattle got rid of its school officers because of the expense.
—The Las Vegas-based Clark County School District has its own police department and places armed officers in and around its 49 high school campuses. Officers patrol outside elementary and middle schools. The Washoe County School District in Nevada also has a police force, but it was only about a decade ago that the officers were authorized to carry guns on campus.
—In Milwaukee, a dozen city police officers cover the school district but spend most of their time in seven of the 25 high schools. In Madison, Wis., an armed police officer has worked in each of the district's four high schools since the mid-1990s.
—For the last five years, an armed police officer has worked in each of the two high schools and three middle schools in Champaign, Ill. Board of Education member Kristine Chalifoux said there are no plans to increase security, adding, "I don't want our country to become an armed police state."
—A Utah group is offering free concealed-weapons permit training for teachers as a result of the Connecticut shootings. Arizona Attorney General Tom Horne proposed a plan to allow one educator in each school to carry a gun.
Ed Massey, vice chairman of the Boone County, Ky., school board and president of the National School Boards Association, said his district has nine trained law enforcement officers for 23 schools and "would love to have one in every school."
"They bring a sense of security and have done tremendous work in deterring problems in school," he said. "The number of expulsions have dramatically decreased. We used to have 15 or 20 a year. Now we have one or two in the last three years."
An officer, he said, "is not just a hired gun. They have an office in the school. They are trained in crisis management, handling mass casualties and medical emergencies."
He said a poster given out by the local sheriff's department shows one of the officers and talks about literacy and reading.
Kenneth Trump, president of the National School Safety and Security Services consulting firm, said having trained officers in schools is "more of a prevention program than a reactive program if you have the right officers who want to work with kids."
But he also criticized a drop in funding for school security, saying, "Congress and the last two administrations have chipped away to the point of elimination of every program for school security and emergency planning."
Dr. Ronald Stephens, executive director of the National School Safety Center that provides training to schools, said the NRA's suggestion of using volunteers "is a whole new concept of school safety." He questioned whether the NRA wants to bring the best sharpshooters on campus.
"How is that going to create a positive atmosphere for young people?" he asked. "How does that work on the prevention side?"
Agundez, 52, who retired as a policeman in 2010, learned shortly before his retirement just how much his trained reaction to a shooter affected students at Granite Hills High.
He was writing a traffic ticket and the driver's whole body started shaking. He had been a student that day nine years earlier.
"He gave me a hug," Agundez recalled. "He said 'I always wanted to thank you.' You saved our lives."