Retired FBI agent Greg Shaffer says hours of training and the right mentality helped the hero cops disarm the man who was shooting up a Louisville bank.
Greg, an active shooter prevention expert with 20 years of experience at the FBI, joined us Wednesday on "TMZ Live," and explained just how difficult it is for police officers to deal with a situation like this, where they can't see the shooter.
Shaffer says the cops clearly had what he calls a "stop the killing before you stop the dying" mindset ... noting how Officer Cory "CJ" Galloway made a split-second decision to go after the shooter, even though his partner, Officer Nickolas Wilt, had just been shot in the head.
As Greg explains, Galloway did the right thing by taking cover and exchanging gunfire with the shooter ... ultimately taking down the killer, all while knowing his partner was in dire straits.
Greg says Galloway mentally stayed in the fight until the threat was neutralized, then went to aid his partner ... telling us it's textbook police training.
Officer Wilt was only 10 days out of the police academy when he responded to the scene ... and he remains hospitalized in critical condition, fighting for his life.
Greg says cops have to rely on their training when dealing with active shooters ... and he's also got some tips for citizens to survive such horrifying scenarios.