And they were about to explode.
Abbott and Corporal Bryan Shaw, both of the El Centro College police department, rushed toward the exit of a school building to investigate the sound of gunshots outside the door.
"You could hear more automatic fire, rapid fire, clear as day," Abbott said. "That's when [the shooter] had us coming out the door to engage."
But before they could make it out, the bullets came to them.
"I saw Corporal Shaw double over a little bit, and the door in front of me exploded," Abbott said.
Wearing his bike uniform -- shorts and a yellow shirt -- Abbott slid backward and fell onto a bed of glass, embedding pieces into his arm and right leg below the knee. Getting up, he turned to Shaw and said what they both now realized: They were outgunned.
"I told him to get our rifles, cause it's a pistol battle against a rifle battle and you're going to lose every time," Abbott said.
Shaw could move, but felt discomfort underneath his bulletproof vest.
"I didn't feel pain, so I assumed it was glass," he said, not knowing that bullet fragments had skirted his vest and lodged in his side.
Neither man had time to care about their injuries. As Shaw went for the rifles and tactical gear, Abbott secured the door. Dallas police officers were outside advancing on the suspect, and as Shaw began to join them, he spotted an officer down.
"He was 20 feet away from the door. I got him, pulled him out of the line of fire and back into the building," Abbot said. "The moment I rolled him over I could see that he was my friend."
A 'fighter, warrior, hero'
Abbott had known Officer Brent Thompson from their days on the police force for Dallas Area Rapid Transit (DART). He recalled working a Christmas night with Thompson and a group of officers who sat down at a restaurant together.
"He went around the table handing out gifts," Abbott said. "He was your friend. He wanted to be there for you if you needed something."
Now those roles were reversed; Thompson needed Abbott as he fought for his life.
"He had been shot in the head and we started to work on him," Abbott said. "We cut his clothes off and saw that he'd been shot in the chest."
Investigators later learned that Thompson had been shot from behind, ambushed as he rushed toward the sound of gunfire. He died at 8:58 p.m., two weeks after getting married to a fellow DART officer.
"Brent was a fighter, warrior, hero, and quite the scrapper," said his wife, Emily Thompson, at her husband's funeral. "The kind of guy you want fighting with you."
They're the qualities Abbott summoned as gunfire again filled the air. The next sound he heard came from his radio. It was Shaw, who was back inside, issuing a warning no one wanted to hear: "He's in the building!"
The 'fatal funnel'
Along with being a police officer, Abbott is a military veteran currently in the Navy reserves. Prior to that, he completed six years of active duty, including tours in Iraq.
"This instance was very similar to Iraq," he admitted. Only this war zone was on home turf -- a terrifying thought, but also an advantage for Abbott and Shaw, who knew the layout of the building.
"We noticed a trail of blood going into the stairwell," Shaw said. Another officer "opens the door and we make entry, and I start receiving shots so I back out."
With Dallas police on the scene, Abbott, Shaw and three other El Centro officers split up to offer advice on the building's layout. Because El Centro's radio frequencies were different from those of Dallas police, Abbott was forced to improvise.
"I grabbed a Dallas sergeant's radio and said 'Look, if he's over here or he's on the mezzanine, he's got access this way. He's got this, he's got that," Abbott said. "And the sergeant said 'How do you know that?' And I was like, 'It's my building,' and he said 'Oh, we need to get you over here.'"
From that moment on, Abbott and an intelligence officer at an off-site command post offered tactical advice and hand-drawn maps to Dallas SWAT officers closing in on the suspect. They boxed him into a corner at the end of a hallway -- good for the public's safety, but tough for officers trying to end the siege.
"If officers entered, it is what they call a 'fatal funnel'," Abbott said, referring to a scenario where police have only one way in and out with no protection.
Hours of negotiations made it clear that the suspect, Micah Johnson, was not going to surrender. Dallas Police Chief David Brown later said Johnson told negotiators his goal was "to kill white people, especially white officers."
Brown authorized his team to take desperate measures: strap a pound of C4 explosive material to a robot and maneuver it against a brick wall. If it worked, the blast would blow the wall inward toward Johnson, killing him swiftly.
"It's a common military tactic," Abbott said, but by all accounts, it was the first time a bomb-carrying robot was used by an American police force.
"This was the safest way," Shaw said in support of the decision. "No other officers were going to get hurt that way."
The bomb worked, ending the bloodshed, if not the tears shed for five officers killed during the gun battle.
'What I signed up for'
Along with DART officer Brent Thompson, four others lost their lives.
Dallas police Officer Michael Krol's lifelong dream was to be a police officer, his uncle told CNN affiliate WDIV. He texted his girlfriend earlier that evening from a march against police brutality to say "Everything has been peaceful."
Michael Smith, once a U.S. Army Ranger, joined the Dallas police in 1989. A family friend said he was so protective of his family that he "never drove his patrol car home." He leaves behind a wife and two daughters.
At six-foot five-inches, Dallas police Officer Lorne Ahrens was often called a "gentle giant." He practiced community policing and volunteered at his children's school.
Dallas Officer Patrick Zamarippa did three tours in Iraq only to be killed here at home. At 32 years old, the father of two was the youngest victim.
"They responded to the calls for help and they gave their lives," said El Centro police Chief Joseph Hannigan. "And yes, they're all heroes."
He includes his own officers, Abbott and Shaw, in that group even if they do not.
"This is what I signed up for," Shaw said. "To protect people."
Shaw will eventually have surgery to remove the bullet fragments from his body, but said he'll be OK.
As for Abbott, his military background not only prepared him tactically, but also mentally, for the trauma he endured. "I'm just going to push on, keep doing what I'm doing," he said. Abbott deploys Saturday with the Navy to help build a runway in Alaska.
His wife, who outranks him as an officer in the military, didn't even know the extent of what her husband had been through until the next morning, Abbott said.
During the standoff he sent a text reading "I'm alive," and that "Everything's good." She said "Okay, I'm going to bed. Wake me up when you get home."
As she slept, Abbott knew he wouldn't be home anytime soon. After getting medical treatment for his wounds, he sent his wife another text: "You're going to be up before I get home. I'll tell you about it later."