By Ben Brumfield, CNN
(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.