BOZEMAN, Mont. -

It's a call no emergency worker ever wants to hear, but one they must prepare for.

"If this ever were to happen in Bozeman, Montana, we don't want that to be the first time we've ever seen this situation," explains Sgt. Travis Munter with the Bozeman Police Department.

The scenario? A man walks into a school cafeteria and opens fire. Faculty, students and staff are trapped inside.

"A drill like this that's kind of a live simulation that a lot of people didn't know the details of made us go through our processes and our procedures, be able to iron out any problems that we have," says Bozeman School Deputy Superintendent of Operations Steve Johnson.

Local law enforcement cut no corners when it came to making this exercise as realistic as possible, complete with an incident command center and even folks from the FBI. We're told this drill is important in case a situation like this were ever to arise.

Multiple agencies participated, from Bozeman and MSU Police to the Gallatin County Sheriff's Office. Fire and ambulances are parked nearby, ready to take away people pretending to be injured.

"I think our systems have worked well. There are things we definitely have been able to learn," says Munter.

They examined everything from building security to communication between different agencies.

"It's interesting when you're talking on the phone with somebody that's locked in an office or locked in a room and the emotions are still there and they're still running," explains Johnson.

Police tell us the school district specifically requested the training for the safety of their students.

They learned they can use more training with all local emergency responders.

Police explain, things ran smoothly when it came to containing the active shooter but say they can improve on working together and clearing communicating expectations between different agencies.