When Sean King drove his pickup truck to Willow Lake in Laurel late Saturday afternoon, there were 50 to 60 people standing around, looking at a boy in the icy water, King recalled yesterday.

"We all knew what had to be done. But nobody was doing it," he said. "So I gave my wallet to a friend and I went in."

King, 32, a member of the Laurel Volunteer Rescue Squad, was credited by Prince George's County police with saving the life of 11-year-old Michael Fabyanic Jr., who fell through the ice while trying to retrieve a football.

As King told the story yesterday, what he did was a matter of "impulse" more than anything else.

"It was just one of those unbelievable situations," he said. "Time was of the essence, and we didn't have much time . . . . It happened so fast. You just act on impulse."

King, who works as a firefighter at Dulles International Airport, said he was driving near his home in Laurel when he heard about an emergency at Willow Lake on his rescue squad radio monitor.

He said he drove to the lake just behind two ambulances and saw a boy about 100 feet from shore, dog-paddling in the water and unable to get closer to land.

Police said two teen-age boys had already jumped in trying to rescue Fabyanic, but they had to clamber back to shore to save themselves before reaching him.

"He was swimming around. Then he would hold onto the edge of the ice with his arms up for a while," King said. "Then he'd slip off the ice and go down. He must have been in the icy water for a good 15 minutes, and we thought he wouldn't come up again. But he was a tough little thing, and he did."

King said he waded into the lake pulling a long rope with a small life jacket attached to it. When the water reached his neck, he said, he swam into the ice.

Then about three yards from Fabyanic, when the ice fragments were too thick to get through, King said, he tossed the rope and life jacket. The boy caught it, and King said he pulled him close enough to grab. Other rescue squad members then pulled them both to shore. King said he and Fabyanic were taken by ambulance to the Greater Laurel-Beltsville Hospital. Officials said both were treated for hypothermia and released in about two hours.

Yesterday, Frances Fabyanic, Michael's mother, said she and her husband learned of the accident only after the boy had been taken to the hospital. She said the family had moved to the Willow Lake Apartments, near the lake on Old Stagecoach Road, just five days earlier from Canton, Ohio.

"Sometimes I think I'm glad that I didn't know what was happening," she said. "It shakes you up. We're just grateful to Sean for rescuing him. We can't thank him enough."

She said that after Michael came home Saturday night he stayed up late drinking hot chocolate. Yesterday, she said, the family took a drive.

King, who is single, said he went to the rescue squad building after leaving the hospital. Then, he said, he went with a friend for a tuna sandwich and a beer.

"I've been on the rescue squad for 11 years," he said, "and I've never been in a situation like that one. But somebody had to get out there. So I did it."