DALLAS -- It can happen any day at any time. Police are training officers on how to deal with an active shooter inside.

"We felt not as a matter of if but a matter of when,” said Captain Dan Birbeck, with the Dallas County Hospital District.

News 8 got an exclusive look at the training. In addition to officers undergoing the training, employees are also learning what to do if they encounter a shooter.

"The faster we respond, the quicker we get in, the less lives that are lost and that's what we're looking to do is stop the killing,” Birbeck said.

Police say hospitals are vulnerable to a possible shooter because people are sometimes in an emotional crisis when they go there.

This week officers are training in the old Parkland Hospital building, which is now empty but has found a new use.

"I would say we are extremely fortunate that we still retain old Parkland right now because it's an awesome training ground,” Birbeck said.

On the night of the July 7th ambush, staff at Parkland feared that a shooter might try to enter the hospital. It’s where police officers who had been shot were being brought in for treatment. They feared a shooter might target officers who rushed to the hospital to check on the injured.

”We locked down our emergency room, driveways, stationed officers at all the major entrances," Birbeck said. "Everyone was vetted that was coming into the building."

Hospital police brought out their high-powered weapons and went into high alert.

Police say they’ve watched shootings at hospitals and other public places increase over the years and decided they needed to step up their training to be ready for anything.