But on Wednesday the San Bernardino, California, officer found himself thrown into the aftermath of the largest mass shooting in America since the Sandy Hook Elementary School massacre nearly three years ago.
He was headed for his lunch break when frantic calls went out for units to respond to the Inland Regional Center. Madden was a mile away and among the first to arrive.
He had trained for events such as this, but he'd never seen anything like it. It overloaded his senses.
"It was unspeakable, the carnage that we were seeing, the number of people who were injured and, unfortunately, already dead, and the pure panic on the faces of those individuals that were still in need and needing to be safe," Madden told reporters.
Fire alarms blared. People groaned in pain and wailed for help. Bodies lay in a room with a Christmas tree and festive decorations.
"Fire sprinklers (were) going off inside the room, so that was adding to the chaos," Madden said.
People said they saw two shooters -- others said there were three. The fresh gunpowder hanging in the air made Madden think that the shooters were still around.
He and other officers who responded had no idea that Syed Rizwan Farook and his wife, Tashfeen Malik
, were already gone -- fleeing in a rented black SUV with their .223-caliber rifles.
The two had killed 14 people and injured 21 more.
When the couple opened fire at Inland Regional, Denise Peraza dropped to the floor as did everyone else around her.
"They were underneath desks, and she was trying to shield herself with a chair, along with a man next to her," her sister Stephanie Baldwin said.
Then a bullet pierced Peraza's back. She phoned her sister thinking it might be the last call she ever made. "I just want to tell you that I love you," Peraza said to Baldwin.
Peraza survived the shooting.
Around the same time, blood-curdling text messages from people trapped at the center popped up on mobile phones in the area.
Terry Pettit got one from his daughter.
"Shooting at my work. People shot."
"Pray for us. I am locked in an office."
Pettit stood outside the center helpless and cried.
Scott Murphy got one from his daughter.
"Active shooter on site. We're all locked in offices and on the floor. Please pray for us," Megan Murphy wrote.
"So, as a parent, as a father, that's kind of like the worst thing that you can have come across your phone," Scott Murphy said.
A few minutes later: "SWAT team is on site trying to secure the building" read a new message on his phone. "I'm in a tiny room with a bunch of people. We're freaking out. Please pray for us."
Inside the center, Madden and his colleagues couldn't get the first 50 people they wanted to evacuate to come out.
"They were fearful in the back hallway area and that actually heightened my concern that -- and my fear that -- potentially the suspects were in that hallway holding them hostage and waiting for us to enter into the hallway," Madden said.
Then the dam broke.
"We had to tell them several times come to us, come to us and ultimately, they did, and once that first person took the motions forward, it opened the floodgates and everybody wanted to come and get away from that as quickly as possible," he said.
Atmosphere of a war zone
With concern the shooters were still there, fear added to the chaos of what seemed like a war zone.
Some people came running out of the center, but officers sent them back indoors.
Officers brought others outside, but they had to keep their hands in the air as they headed to a neighboring golf course.
Once in safety there, some joined hands and prayed. A few fell into each other's arms and cried.
"We stood there for hours, hours, witnessing clothing of deceased ones on the street, people crying, co-workers crying, us wanting to get to our children," a woman who works at the center said.
Lines of heavily armed officers held their weapons at a tense ready. Wounded people were brought to a triage center. Some were on stretchers. Some were rushed to the hospital.
Elsewhere in San Bernardino, another shooting scene erupted.
Officers following a tip had gone looking for Farook at his residence in nearby Redlands. The gunman and his partner, Malik, drove by. Police pursued them as the couple sped back to San Bernardino.
As Malik drove, Farook fired out the window at police.
The gunbattle ended with police riddling the SUV and the shooters with bullets.