NEWTOWN, Conn. — A worker who turned on the intercom, alerting others in the building that something was very wrong. A custodian who risked his life by running through the halls warning of danger. A clerk who led 18 children on their hands and knees to safety, then gave them paper and crayons to keep them calm and quiet.

Out of the ruins of families that lost a precious child, sister or mother, out of a tight-knit town roiling with grief, glows one bright spot: the stories of staff members at Sandy Hook Elementary School who may have prevented further carnage through selfless actions and smart snap judgments.

District Superintendent Janet Robinson noted “incredible acts of heroism” that “ultimately saved so many lives.”

“The teachers were really, really focused on their students,” she told reporters Saturday.

Some of them made the ultimate sacrifice.

After gunman Adam Lanza broke through the school door, gun blazing, school psychologist Mary Sherlach and principal Dawn Hochsprung ran toward him, Robinson said. Hochsprung died while lunging at the gunman, officials said.

The 56-year-old Sherlach, who would have been tasked with helping survivors cope with the tragedy, died doing what she loved, her son-in-law, Eric Schwartz, told the South Jersey Times.

“Mary felt like she was doing God’s work,” he said, “working with the children.”

Just this past October, Hochsprung had tweeted a picture of the school’s evacuation drill with the message “Safety first.”

Victoria Soto, a 27-year-old teacher, reportedly hid some students in a bathroom or closet and died trying to shield them from bullets, a cousin, Jim Wiltsie, told ABC News. Those who knew Soto said they weren’t surprised.

“You have a teacher who cared more about her students than herself,” said John Harkins, mayor of Stratford, Soto’s hometown. “That speaks volumes to her character, and her commitment and dedication.”

In other cases, staffers both saved students and managed to escape with their own lives.

Teacher Theodore Varga said that as gunfire echoed through the school, a custodian ran around, warning people. He appears to have survived; all the adults killed were women.

“He said, ‘Guys! Get down! Hide!'” Varga said. “So he was actually a hero.”

Someone switched on the intercom, alerting people in the building to the attack by letting them hear the chaos in the school office, a teacher said. Teachers locked their doors and ordered children to huddle in a corner or hide in closets as shots echoed through the building.

In a classroom, teacher Kaitlin Roig barricaded her 15 students into a tiny bathroom, pulled a bookshelf across the door and locked it. She told the kids to be “absolutely quiet.”

“I said, ‘There are bad guys out there now. We need to wait for the good guys,'” she told ABC News.

One student claimed to know karate. “It’s OK. I’ll lead the way out,” the student said.

Clerk Maryann Jacob was working with a group of 18 fourth-graders in the library when the shooting broke out. She herded the children into a classroom in the library, but then realized the door wouldn’t lock.

They crawled across the room into a storage space, locked the door and barricaded it with a filing cabinet. There happened to be materials for coloring, she said, “so we set them up with paper and crayons.”

One person who wasn’t in the school at all also is getting props for his grace: Robbie Parker, whose daughter Emilie died.

Speaking to reporters Saturday, he said he was not mad and offered sympathy for Lanza’s family.

“I can’t imagine,” he said, “how hard this experience must be for you.”