Jack Thomas looked like a kid who planned to play a practical joke on his friends. He grinned, his eyes flashed, and he lowered his voice so as not to let anyone else hear what he was about to reveal.

“That’s the suspect suitcase,” he said, pointing to a piece of luggage separated from the scores of men and women lying on the floor at the Green Airport ticket counter. Some were still, as if they had gone to sleep, maybe even dead. Others were crying out for help while still others were writhing. All wore yellow T-shirts.

Thomas didn’t pay attention to the masses. His focus was on the suitcase.

“See that coffee maker?” It was plugged into the wall beside the suitcase. “That’s hot water.”

Thomas had a plan; in fact, the suitcase and coffee maker were a small part of a far bigger plan that he and representatives from other agencies have worked on for the past year.

“Well,” said Thomas, lowering his voice again, “there’s dry ice in the suitcase.”

He knew when the hot water was poured on the dry ice, smoke would emanate from the suitcase. There was more to the suitcase, which in the scenario played out Thursday night contained nerve gas responsible for felling so many of the passengers lying in front of Green Airport’s northerly ticket counter. The suitcase also contained a canister of compressed air that would lend even more authenticity to the drill played out over a couple of hours.

Thomas, chief of the Rhode Island Airport Corporation Fire Department, watched the plan come together with satisfaction. Shortly after 9 p.m., the volunteer travelers lined up at the ticket counter started keeling over. They were coughing. Some tried leaving the scene but collapsed. A few were in wheelchairs, and Thomas said there were blind and deaf people in the crowd. The group of “victims” also included students from Salve Regina University and the full 24-member Warwick Fire Department recruit class.

As stricken passengers fled, airport police responded. One of them, after checking one of the fallen, also succumbed to the gas. It was all part of Operation Terminal Dose.

Warwick and North Kingstown fire departments responded to the scene.

“They have to try to figure out what is happening,” Thomas said as the first of the firefighters arrived. But they weren’t equipped to deal with a release of potentially lethal gas. The scene went silent as the firefighters retreated. The volunteers were given a respite. They could step out of character, or actually, go back to being themselves. They sat up. They talked and some took the break for a visit to the restrooms.

Outside on the departure level in the reflection of flashing lights, firefighters and police had set up an informal command center. They erected a decontamination tent for those taken from the terminal. Crews suited up in decontamination outfits designed to keep them from either breathing the contaminated air or coming in contact with the hazardous gas. Rescue vehicles stood by. And as all part of the plan, hospitals and key officials were notified of the situation.

RIAC interim president and CEO Peter Frazier, who was watching the exercise with Peter Gaynor, director of Rhode Island Emergency Management, reached into his pocket to retrieve his buzzing cell phone. The screen read “code red.” He was being alerted as the plan dictated. He would be expected to monitor the situation. A more active role was expected of others who polled hospitals to determine the numbers of available beds and alerted hospitals of the pending influx of patients.

In past exercises, these were “paper patients,” a sheet of paper describing a victim’s conditions. This time there were tags listing symptoms worn by each of the volunteer victims as well as attached to 200 inflatable dummies. That was Thomas’ doing again.

Thomas said the Federal Aviation Administration requires a live full-scale exercise like that performed Thursday be conducted every three years. Tabletop exercises are performed in the interim years. In addition to RIAC police aircraft rescue and firefighters, among other agencies and groups participating in the exercise, were the Warwick and North Kingstown fire departments, the Hospital Association of Rhode Island, Rhode Island Emergency Management, Rhode Island Department of Health, Rhode Island State Police, and the Rhode Island Department of Environmental Management.

An hour into the exercise that was scheduled not to conflict with departing flights – arrivals on the lower level were not delayed – the passenger who allegedly left the suspect suitcase had been apprehended.

But the victims of the incident still were moaning, coughing and calling for help as HAZMAT crews responded according to protocol. Those playing dead were left to the last, including Thomas’ wife, who had volunteered for the role.

“She’s dead,” he said as a matter of fact. And then he took another look.

Was that his wife taking a selfie?

It made for some laughs at an otherwise serious event that went on into the night.