(CNN) -- Facing down a gunman, placing yourself in the path of flying bullets, forfeiting your life to protect innocents. It's a job description fitting for a soldier or police officer, but for a school teacher -- an elementary school teacher at that?
What the teachers and principal at Sandy Hook Elementary School did for the children in their care could win a soldier in a war zone a Purple Heart.
But the soldier makes a conscious choice to face mortal danger when he or she enlists. Sandy Hook's heroes did not.
Adam Lanza did not give them that choice when he opened fire in the hallway and two classrooms Friday in Newtown, Connecticut.
Long before it happened, Principal Dawn Hochsprung tried to prevent a shooting -- or any other calamity -- by implementing new security measures at Sandy Hook. She made sure teachers practiced getting into lockdown mode.
The front door was locked when the gunman arrived. A mother meeting with Hochsprung about her struggling child was astounded that the gunman had gotten in: "It's a locked school; you have to be buzzed in," she later said.
Lanza blasted his way in.
Hochsprung heard the loud pop. She, school psychologist Mary Sherlach and Vice Principal Natalie Hammond went to investigate.
They were acting as the first line of protection and paid heavily for it. Only Hammond returned from the hallway alive -- but not unscathed.
Along with Hochsprung, 47, and Sherlach, 56, four teachers perished.
Victoria Soto, 27, moved her first-grade students away from the classroom door. The gunman burst in and shot her, according to the father of a surviving student.
"She would not hesitate to think to save anyone else before herself and especially children," her mother, Donna Soto, told CNN's Piers Morgan.
Anne Marie Murphy's body was found in a classroom, slumped over young children killed in the shooting. The 52-year-old special education teacher was apparently attempting to shield them, her father told the newspaper Newsday.
Aspirations were cut short and potential was wiped out -- of the young children who will no longer learn and grow toward adulthood, but also of the teachers who died.
Rachel D'Avino, 29, was a behavioral therapist who worked with autistic children. D'Avino's boyfriend was going to propose to her on Christmas Eve.
Lauren Rousseau, 30, had dreamed of being a teacher since before she went to kindergarten herself. She had been hired only last month by Sandy Hook and was substituting for a teacher on maternity leave when Lanza killed her.
For the teachers who lived through the carnage, difficult tasks lie ahead.
In the coming days, they will bury their colleagues and 20 small children they taught and adored, while comforting parents and nursing the tender hearts of the children who survived.
Kindergarten teacher Janet Vollmer knows at least half of the killed children.
"Ten of them were in my class last year," she told CNN's Anderson Cooper on Sunday. "It's tough. It's tough."
When the shots rang out, Vollmer locked her classroom door, covered the windows, including the one in the door, then took the children into a nook between bookcases and a wall.
She read them a story to keep them calm.
"They kept saying 'How come we're here for so long?' 'Well, it will be a little longer.' " she answered. "When they're 5, you do whatever you can to keep them safe and keep them calm."
"We're going to be safe," Vollmer told them, "because we're sitting over here and we're all together."
First-grade teacher Kristen Roig herded her students into a bathroom, locked the door and told them not to make a peep.
They got impatient, antsy, wanted someone to go out and see what was happening. No, she told them. She was afraid they would all die.
"If they started crying, I would take their face and tell them, 'It's going to be OK.' I wanted that to be the last thing they heard," she said, "not the gunfire in the hall."
The wait dragged on, Vollmer said.
"Maybe it was 20 minutes, a half-hour; I'm not sure."
Police knocked at the door to take them all out. They instructed her to have the schoolchildren hold hands and close their eyes.
"At 5, it's not so easy to close your eyes and walk," Vollmer said. "So I had them look toward the wall." They all had to be brave.
President Barack Obama eulogized the teachers in a speech to Newtown and the nation Sunday night.
"They responded as we all hope we might respond in such terrifying circumstances -- with courage and with love, giving their lives to protect the children in their care," he said.
"We know that there were other teachers who barricaded themselves inside classrooms, and kept steady through it all, and reassured their students by saying 'Wait for the good guys, they're coming'; 'Show me your smile.'"
Now Newtown will need to muster the courage to rebuild, to keep raising the siblings of fallen angels, to face another day without a beloved child.
Sandy Hook Elementary will probably move into another building, away from the scene of the spilled blood and bullet holes. Teachers and children will go back to class, prepare lessons, do homework, take tests and grade them.
"We need to get the kids back in school," Vollmer said.
Vollmer, her colleagues and the children have all seen and heard too much and gotten through it bravely. Even soldiers experience permanent trauma after seeing a child being killed -- let alone 20 at once.
The stories of how these teachers and school administrators risked their lives -- and in six instances gave them -- to protect their young students spurred CNN readers to label them heroes.
"The next time people criticize teachers, think of these heroes and know that any teacher would do the same for their students. Your children," wrote Tom in the online comment section below this story. "How many dozen lives were likely saved because the teachers and administrators knew what to do?"
"Let's try and remember these heroic women's names and forget the gunman's name starting today," said a person using the name druglady33.
Margaret Kime called their actions "Unimaginable grace when faced with unimaginable horror."
Commenter marsh025 suggested the school principal should have been armed and able to fight off the attacker:
"She should have come out with guns blazing. (I never thought I would say that) At the very least, principals need to be armed and trained in locating and engaging gunmen who enter their schools. The principal and a security/police officer should go together, armed to confront the individual. This is what we've become."
"We should never forget them," wrote boogbop, "and we should make certain they did not die in vain by holding them up as an example of what is great and good in human beings."