Keith Lyons, 13, had been in Boy Scout Troop 148 two years and he knew all the rules for helping a drowning person: lift him from the water, tilt his head to open the breathing passages, talk to him calmly and call for help.

Lyons said he didn't even have time to think Wednesday afternoon before putting his training to work helping a man who had toppled into the creek in Arlington's Lubber Run Park.

Arlington paramedics credited Keith, 12-year-old Owen Lawson and 14-year-old Matthew Sanders with saving the life of Tracy Moody, 20. Moody suffered an epileptic seizure and fell backward into the creek about 3 p.m. Wednesday, said paramedic Robert Gray.

When Gray and other paramedics arrived at the park, they found Owen and Keith holding Moody's head above the foot-deep water, talking to him softly as he slowly regained consciousness, Gray said.

Moody "went down into the water," Gray said. "If he hadn't been held above water, he would have drowned."

Keith said yesterday that he was more startled than scared when Moody toppled into the shallow creek.

The three boys, who all will enter eighth grade at Kenmore Intermediate School in September, were spending their first afternoon of summer vacation chatting on the rocks near Lubber Run when Moody walked by, Matthew recalled.

"We started to talk to him for a while. We were joking around. All of a sudden, he just stood up and stepped in the creek. He just kind of flopped down into the water and fell on his back," Matthew said.

"He just keeled over in the creek right in front of us," Keith said.

Seconds later, they noticed Moody's head had dropped back into the water, Keith said, and Owen ran to hoist him up.

Owen, whose mother said he has been a Boy Scout for five years, was out of town yesterday.

While Matthew, who is not a scout, raced up the bank to call for help, the boys said, Keith and Owen pulled Moody partly out of the water and propped him on a rock.

"I could sort of hear Moody breathing. We tipped his head back, opened his mouth and let the water come out," Keith said.

Moody was treated for an epileptic seizure at Arlington Hospital and released. He could not be reached yesterday.

While fire officials praised the boys' quick thinking yesterday, Keith was taking his heroism in stride.

"We mostly did what we were supposed to do," he said. " [Owen and I] are both in the Scouts, so we're prepared for things like this."