"I really began to feel sorry for him," she told Cooper, adding that the suspect told her he was off his medication and considering suicide. "I knew that where he was at mentally was not a good place. But I knew that he was there, for whatever particular reason, in life."
The man with the rifle eventually let it be known, via Tuff, that he was no longer threatening to shoot any police officers who approached; by then, he was communicating with them about where he should put his gun, where he should get down on the ground in surrender, and how police would come and get him.
As all of this unfolded, the dispatcher talking to Tuff largely remained silent -- except a few brief acknowledgments about what she'd heard and the constant clatter of her keyboard.
In her heart and behind the scenes, though, McCray was sweating it out. Thankfully, she had a "true hero" partner in Tuff who, with her clear descriptions and calm demeanor, made it so the call-taker and thus police could very easily "visualize what she was seeing and what she was going through."
Even to the end, emotions ran high. The suspect started getting "agitated" after he'd decided to surrender, standing back up and taking a drink of water because police had yet to come and get him.
Recognizing what was happening, McCray said she put her phone on mute.
"I'm hollering across the (dispatch) room: 'Hey, he's getting agitated, we need to move.'"
They did get inside the Decatur school in a flurry soon thereafter, surrounding and detaining Hill.
That was then, finally, both Tuff and McCray could breathe a sigh of relief.
"You did great," McCray said to Tuff 31 long minutes after that first call came in. "You did great."
Hill, meanwhile, was swiftly taken away by law enforcement officers and now sits in a Georgia jail awaiting charges that likely will include aggravated assault on a police officer, making terroristic threats and false imprisonment, according to authorities.
Tuff would like to visit him, calling him a "hurting soul" who she'd like to help.
"We all go through something," she said, with her 911 call reflecting on her challenges raising a disabled child and suicidal thoughts after the end of her marriage after more than two decades. "And I believe that God gives us a purpose in life."
And Tuff believes she was meant to be at McNair on Tuesday, even though she'd originally been scheduled to be off. She thinks she was meant to be up front to first encounter the gunman -- in that location at that time because she'd been delayed from going back to her desk. She said it was all part of God's plan -- for her, for the suspect and for McNair's students.
But that doesn't mean Tuff knew she had it in her, to face down a gunman and potential death so calmly, and to live to tell about it.
"No, no. If somebody would have told me that I was going to be doing that that day, I wouldn't have believed it," she told CNN. "God has a way of showing you what's really in you."