Lt. Mike Madden, an administrative commander for the San Bernardino Police Department and a 24-year veteran, usually holds what most consider as a "desk job."
But was on his way to lunch at 11 a.m. on Wednesday, he heard the call came over the radio and he responded to the Inland Regional Center.
"I was nearby, I was less than a mile away," he said. "As I got closer I realized I was one of the very first units there. Myself and Officer Shawn Sandoval arrived almost simultaneously."
MORE: Acts of heroism praised following San Bernardino mass shooting
Madden said though law enforcement members are trained for active shooters, they can never actually be prepared for what they'll witness.
"Although we train for it, it's something that you're never actually prepared for it," Madden said on Thursday as he addressed the media.
Lt. Mike Madden addresses questions from the media on Thursday, Dec. 3, 2015.
Madden said within two minutes of his arrival, they had four officers at the scene and they assembled as a group to run around the south side of the building to enter inside the east side of the building.
"I was asking officers to respond as quickly as possible because we had every belief at that time that we had people actively being shot inside the building," he recalled. "We wanted to get in there and we wanted to stop any further innocent people from being injured and possibly killed."
MORE: The 14 victims of the San Bernardino mass shooting
He said as he entered the building, the reports over the radio were confirmed as he found victims either dead or with injuries.
"As we entered the conference room, the situation was surreal," Madden said. "It was unspeakable carnage we were seeing."
Madden said he and his team had a hard decision to make, having to choose to help victims crying out for help or pursue the shooting suspects in order to prevent more innocent people from being shot.
"That was a difficult choice to have to make as well, passing people we knew were injured and in need of assistance, but our goal at that time had to be trying to locate the shooters and deal with them," he stated.
In all, 14 people were killed and 21 others injured in the attack that police said was orchestrated and carried out by 28-year-old Syed Rizwan Farook and 29-year-old Tashfeen Malik.
Farook and Malik were later killed in a hail of gunfire following a gun battle with officers a mile south of the IRC building.
MORE: What we know about the San Bernardino mass shooting