The “scenario” went like this: A lone gunman entered Lakeridge Elementary at 9 a.m. Inside, he opened fire on staff and students. Fourteen people were injured, and three died.

These are words spoken after a tragedy that Islanders never want to experience. But, if they ever do, their first responders, city staff, school district employees and regional partners are as prepared as they can be.

The city held a full-scale emergency drill on Thursday morning, bringing in 350 people, including many volunteers, to make sure that the response to an active shooter in a school was safe, efficient and as realistic as possible.

Policeman and firefighters arrived at the scene, going through the motions of finding the shooter (who had “died” from a self-inflicted gunshot wound), sweeping the school to look for other gunmen, aiding the injured, evacuating the kids and eventually reunifying them with their families.

“When I arrived, I saw a lot of people efficiently doing their jobs,” said Mayor Bruce Bassett, who took part in a mock press conference with MISD Superintendent Gary Plano, Fire Chief Steve Heitman and Police Chief Ed Holmes near the end of the drill. “I give kudos to Jennifer Franklin.”

Franklin, the city’s emergency manager, had been preparing for the drill for months. She said that exercises like these help the city improve its emergency plans and protocols, especially with feedback from volunteers and evaluators.

“This is how we make it better, not just for us, but for the kids… So we can keep them as safe as possible,” she said during a debrief at the end of the drill.

The exercise hit home for many with memories of shootings at Sandy Hook in Newtown and most recently and locally, Marysville Pilchuk High School.

One of the drill evaluators, City of Shoreline Emergency Manager Gail Harris, said her team did an active shooter drill three days after the tragedy in Marysville.

“It was emotional, but we figured that we had to learn,” she said.

Harris gave the emergency management team several tips and ideas after the drill, including a critique of the mock press conference. She told city officials to be very specific about messaging regarding memorials and appropriate donations.

“You would have international media here in minutes,” she said. “Newtown got 60,000 teddy bears. But they lost kids, they didn’t lose teddy bears.”

Harris and other evaluators acted as “reporters” during the press conference, asking about implications for gun ownership, the role of social media and whether teachers should be armed — topics that mirrored national discussions following a school shooting.

Plano said he is concerned about easy access to guns.

“Every day I wake up worried about the safety of our kids,” he said. “It is one of my, if not my worst nightmare to have an active shooter in a school.”

He said security in Mercer Island schools could be improved by locking front doors, and having a secretary’s office in the front hallway so district employees can watch as people enter and exit the building.

Heitman said that following recent events, it had become a “high priority to train for this type of situation.”

Holmes said that balancing the right to carry a firearm with the responsibility to keep people safe is tricky, but that Washington’s newly passed initiative, I-594, places some limits on who can acquire guns by expanding background checks.

“It’s a tough exercise, and it’s normal to have reactions to this,” Franklin said. “We really hope that this is something we never, ever have to experience, but after going through this process, I feel a lot better.”