It was a sobering experience at St. Joseph High School last week as fire alarms were going off, yells were coming from classrooms and fake gunshots echoed through hallways. In each training exercise, Trumbull Police officers rushed in to respond, confronted with the unexpected and needing to act quickly.

It was the first time the department has trained in a school for what police call an “active shooter” incident.

“St. Joseph has been so generous to let us use their facilities,” Police Chief Thomas Kiely said last Wednesday. “We train down at the shooting range and we’ve trained at the mall, but this is our first time in a school.”

Students in the Trumbull Police Explorers program played victims in the scenarios.

The most important part of any active-shooter emergency is a rapid response, Kiely said. All officers in the department were trained last week in a number of different scenarios, including recognizing and dealing with IED’s, learning how to use emergency medical kits that can control bleeding of injured and deploying K-9 units to help in response. The emergency medical kits given to officers, to wear on their belts, provide a number of tools, many used by Boston Police after the marathon bombing, to help save lives. Police have also worked with Trumbull EMS in planning for a worst-case scenario, making sure police can get injured victims to medical responders safely.

“It’s almost sensory overload,” Kiely said of the some of the training. “We give a lot of feedback on this. It has to become second nature.”

St. Joseph President William Fitzgerald stopped by to observe some of the training last Wednesday.

“We feel it’s mutually beneficial,” Fitzgerald said. “If the police department is familiar with the school, our safety is enhanced.”

“Overall, it will make the community safer,” Kiely agreed.

Police were filming each training session, to review every team’s strengths and weaknesses

“They are debriefed on everything they did right and everything they did wrong,” Lt. Leonard Scinto said.

As one group came through an exercise and failed to communicate, Scinto said “that’s why we’re here, to learn.”

Officer Scott Duva, who was replaying some of the exercises, said training at the school was a huge benefit.

“This is the most realistic training we can do,” Duva said. “Paper targets don’t shoot at you.”