BAILEY, Colo. -- Emily Keyes died a hero.

Just ask anyone on the Jefferson County Regional SWAT team.

One year ago, a gunman walked into room 206 at Platte Canyon High School, took hostages and ultimately murdered Emily.

What was never told was the full extent of her heroism.

The gunman refused to talk with negotiators or police, so Emily became the voice in the classroom.

She kept the window of opportunity open so her classmates could get out and SWAT officers could get in place.

"She was certainly the one keeping things calm," said Sgt. Grant Whitus of the Jefferson County Regional SWAT Team.

He and Sgt. A.J. DeAndrea were stationed on either side of the door to room 206, making plans for entry, while Officer Stacy Jarvis tried desperately to negotiate with the gunman.

"For people to say there were ever really negotiations is really not accurate. He never really communicated at all," Jarvis said.

It had been nearly a year since the shooting when 7NEWS spoke with Jarvis outside room 206.

Jarvis told 7NEWS, "[There was] some exchange back and forth but that was just telling law enforcement to get out of there."

Inside the room, Emily Keyes and another teenage girl remained as the gunman had, inexplicably, released five other hostages.

It was Emily who began communicating, despite having a gun to her head.

"Terrible things were going on in that room and had gone on in that room and for her to keep herself together the way she did, I don't know how she did it," Jarvis said. "She did yell at us a couple times and again I talk about her guts and her strength."

DeAndrea told 7NEWS, "This person was a total coward. He was hiding behind two little girls."

He went on to say, "She would control things inside there. You could tell, just by her demeanor. "

Then the gunman heard someone on the roof.

Emily screamed.

"He began yelling. The girls began to yell. You could feel the tension. Everything rose up and I'm looking at Grant ... and we're looking at each other going 'we're gonna have to go,'" DeAndrea told 7NEWS.

Whitus said, "I honestly thought he was going to shoot one of them."

"You've got this mass chaos going on and then comes this calm beautiful voice. It's Emily and she calms the whole thing down," said DeAndrea.

Remembering that moment, Jarvis said, "The psychological stress she must have been under is horrendous. And to be able to carry herself in the way that she did is phenomenal. I think Emily's performance that day allowed for other girls to be saved."

DeAndrea said, "She's remarkable. Absolutely just a remarkable individual and the world is a lesser place because she's not here anymore."