LeeAnn Grant, 20, said she fled as Derrick Brun rose from his desk at Red Lake High School to confront 16-year-old shooter Jeff Weise, ignoring Grant's pleas to run.
"I know he bought me time by confronting Jeff, for me to even get that much farther away with the students," Grant told The Associated Press on Wednesday. "Derrick's my hero ... He didn't even look scared. He didn't look worried. He knew what he was going to do."
A so-called psychological swat team run by the National Association of School Psychologists Thursday began to work with members of the community, reports CBS News Correspondent Stephan Kaufman. The team members come from around the country.
The association's president-elect, Dr. Bill Pfohl, said the team members were in northern Minnesota not to preach, but to listen.
"The job is mainly to be a good listener. We allow people to tell their stories about what they experienced with this particular trauma," he said, adding that the counseling is available for parents, teachers and other adults, as well as students.
The "psychological SWAT team" will remain in Red Lake for three to five days.
"The real important part is to start to set up a system that will last over the next several months, if not years, because we know that events can have delayed reactions up to a year away," Pfohl told Kaufman.
Even relatives he lived with were blind to the building rage that led Weise to gun down nine people, wound seven, and take his own tormented life, reports CBS News Correspondent Bob McNamara.
"We don't know what went on," his aunt, Shauna Lissuer, said. "We'll never know. We'll always ask the question, 'Why?'"
In its Thursday editions, The Washington Post reported that a bus driver for a health center said he drove Weise to Thief River Falls in June, where the boy was going voluntarily to a psychiatric ward.
The newspaper also cited a cultural coordinator at Red Lake Middle School who said Weise had been hospitalized at least once for suicidal tendencies and was taking the anti-depressant Prozac.
As details about the shooter's background emerged, one of the victim's victims told another story of bravery amid the carnage.
At a news conference at MeritCare Hospital in Fargo, N.D., family members said injured student Jeffrey May, 15, tried to protect two girls by stabbing Weise in the side with a pencil.
Weise shot him in the right cheek and the bullet lodged in his neck. The 6-foot-4, 300-pound teen suffered a stroke and can't move his left side, but he has been able to write notes to his family.
Doctors don't know if May will recover, but his family said he was breathing on his own, which they called a good sign.
Grant said she and Brun were working at the doors of Red Lake High School as usual on Monday. Three of the four doors were locked; the open door funneled students through a metal detector.
Grant described Weise stepping out of his grandfather's police truck — taken after the 16-year-old boy had killed the man and his companion, according to authorities — and sending two shotgun blasts into the air.
Just four years older than Weise, Grant had known him for years and recognized the 6-foot, 250-pound student at once. His black trench coat billowed open and Grant saw more guns on the boy's belt.
She had no gun, no bulletproof vest and a little girl and a little boy at home. She had just begun working as a security guard in August.
Outside, the gunman tried one door, then another.
"He looked right at me. I made eye contact with him," Grant said. The boy quickly found the open door.
"He walked in and fired another shot and I was telling Derrick, 'Come on, let's go. Let's go, Derrick. Run. We need to save these kids, we need to do something.' And I radioed in ... 'There's a guy coming in the school and he's shooting and he has a gun.'"
"Derrick just sat there at his desk. ... He just kept staring at Jeff. I kept hollering for him to come with me. He wouldn't come, he just stayed there."
The noise drew students toward the front doors. Some thought maybe there was a fight, and they wanted to see, Grant said.
"I start yelling at them, 'Run! There's a guy with a gun here! Just run!' And then I took off to try to protect them," she said.
"I turned back a little bit, and you could see Derrick kind of getting up, going right toward Jeff," she said. "And then I heard two shots again."
Other witness accounts indicate that's when Brun was killed.
Grant said the gunman caught up with her and some students but eventually turned down another hall, and Grant and the students made it out of the building.
"I hope this is a wakeup call and my son didn't die in vain," Francis Brun told reporter.