San Bernardino (CA) PD Lt. Mike Madden entered a center for people with developmental disabilities with three other San Bernardino police officers Wednesday. There, he found 14 people dead and 21 wounded in the nation's worst mass shooting since the 2012 attack at Sandy Hook Elementary School in Newtown, Conn., reports the Los Angeles Times .

"The situation was surreal," Madden, a 24-year veteran, said Thursday night. "It's something that we prepare for, and an active shooter, they talk about sensory overload. … It was all of that and more. It was unspeakable the carnage we were seeing."

Madden's recollections, along with recordings of Wednesday's police radio traffic, show how quickly the events unfolded as 300 officers from various agencies sped to the scene, evacuated the victims, and tracked down the suspects.

Law enforcement experts on Thursday praised the San Bernardino Police Department, San Bernardino County Sheriff's Department, and others for their handling of the incident.

"There was a very short response time, they did a follow-up very rapidly and got on top of the suspects," said Scott Reitz, a former Los Angeles Police Department SWAT officer and instructor. "I'm absolutely impressed. That sometimes takes hours or days."

The San Bernardino officers "did what they were supposed to do: come to the location, get together with a team of three or four or five officers and make entry," said San Marino Police Chief John Incontro, a former LAPD captain who oversaw the department's SWAT team. "The goal is to find the suspect and stop the threat."