While Tuff worked to keep the gunman calm and spoke with him, she signaled a code to her two counterparts, who immediately triggered a phone tree to tell teachers to lock doors and send children to safety, Hudson said.
"Her name, Antoinette Tuff, says everything about her," said Brian Bolden, the school principal. "Tough. She has always been that way, from the first time I met her."
He describes her as a strong leader whose authority everyone respects.
The past eight years, Tuff has been with the Georgia school -- the past three at McNair.
And she almost wasn't there Tuesday. Tuff was scheduled to be off that day, but because of a shift change, she ended up right where the school needed her to be.
The school's existing safety procedures will remain the same while the investigation takes place, Bolden said.
But he promised any needed changes will happen. "We will do everything humanly possible in our power to keep this next generation of learners safe."
Counseling was made available to the kids, and the school understands that some children might not be ready to come back right away, he said.
Inside the suspect's mind
On Wednesday night, Hill, 20, was in a Georgia jail awaiting a still undetermined initial court appearance.
Authorities are still hammering out exactly what charges he will face. Police spokeswoman Mekka Parish has said they would include aggravated assault on a police officer, terroristic threats and possession of a firearm by a convicted felon. Ray Davis, the lead detective on the case, added that false imprisonment and "several weapons charges" probably will be included as well.
Whenever the charges come down, Hill will waive his initial court appearance, said Claudia Saari, public defender for the Stone Mountain Judicial Circuit. She said members of her office's mental health division are handling his case and declined to make any further comment.
This week's incident is not Hill's first run-in with the law. He has a criminal history in DeKalb and neighboring Henry County that, while not "lengthy," does include violence, Davis said.
Specifically, Hill pleaded guilty in July to making "terroristic threats and acts" against his brother.
Henry County court records show that, in addition to three years of probation, he was ordered to attend anger management classes. But that county's district attorney, James Wright, said Wednesday that there's no indication that Hill completed them.
As to any connection to McNair Discovery Learning Academy, why he might have gone into it armed, and what he planned to do once there, authorities have not outlined a motive or a detailed plan.
Being from DeKalb County, Hill "possibly had been there (at the school) before speaking with some people in the administration," Davis said. But "there's no indication he had a grievance with the school."
Before he entered the school, the suspect took a picture of himself with the assault rifle -- which he'd taken "from the house of an acquaintance," said Davis, who did not say whether the weapon was stolen.
So did Hill go in intent on killing people?
Davis responded: "I believe there was something else, but I don't want to go into detail."