For more than four hours, Larry Gordon was buying time.
He had more than a decade of crisis negotiation experience to rely on, but what was unfolding inside El Centro College was different.
The gunman whom Gordon was speaking to had just killed four Dallas police officers and a DART police officer. He was holed up with a semi-automatic assault rifle in a second-floor hallway riddled with bullets.
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"He was telling me that he was going to die by my bullet or his," Gordon said.
A robot carrying an explosive would eventually kill the shooter, Micah Johnson, and end the standoff.
Eighteen months later, Gordon and all of the officers involved in the operation have been cleared of any wrongdoing.
Now they're ready to share their stories.
"It's a relief, and honestly, for me, it's therapeutic to talk about it, to get it out," Gordon said.
As lead negotiator Gordon's objective was to keep the shooter talking. If he was talking, he wasn't shooting at officers who needed time to figure out how to strap explosives to a robot and deliver it to the gunman.
"I had to get him to stay in that position until we could find out what we were going to do with him. It was just a chess match," Gordon said.
Tone is important in negotiations. In a recording of their conversation Gordon is heard speaking calmly, trying to reason with the suspect.
The shooter refused to give Gordon his name, instead he asked to be called "X."
"You know what's going to happen, 'X?'" Gordon asked. "If you kill yourself, you know what's going to happen? The media is going to tell their own story."
"I don't care," Johnson responded. "My people will know what I've done."
Gordon learned quickly that there was a racial dynamic in the negotiation. The gunman had come downtown to kill white police officers working a peaceful protest in Downtown Dallas.
The negotiator used race to try and build a rapport with the shooter.
"I have a habit of saying 'bro' to people," Gordon said. "The question he asked me, I said, 'We can't do that, bro.' He said, 'Don't call me brother. I'm black, you're white. I'm not your brother.'"
Once Gordon convinced him he was black, the shooter's motive became clear. He was angry about the recent shootings of black men by police across the country.
"Once I got him convinced that I was black, I think that's when I knew (police shootings) was the issue, along with some other thing he was saying about race," Gordon said.
That part of the conversation still lingers with Gordon because he understood the reason why the shooter was angry.
"I tried to show empathy. Being African-American myself, I understand. That was not the way to go about it. What he was doing was not the way to go about it," Gordon said.
The negotiation sounded similar to the conversation Gordon had with a family member earlier that day.
"I was talking to my niece about police and relationships with the minority community right when I heard 'officer down' on the radio," Gordon said. "When I hung up with her and went to the location, got inside of El Centro, me and him had the exact same conversation."
Today, Gordon can listen to the recording and feel nothing. He's become desensitized to it.
The standoff and the shooter no longer have power over Gordon, but their conversation still lingers in his ears.
"The fairness aspect of what he was talking about, and how someone can be pushed to that point — to strap on a vest, go downtown, get a rifle and shoot at the police and take on a full-fledged SWAT team — that sticks with me," Gordon said.
"We have to be more honest, more transparent, and more on point when we deal with the public. Treat people with fairness, treat people with kindness, and be empathetic to people."