Evelyn Shipmen, a 57-year-old widow, keeps a loaded pistol and a "mean biting dog." Marcy Messine, 68 and also a widow, checks the bolts on her doors whenever she hears noises in the night.

It's all part of living near the District of Columbia's Lorton Reformatory, in Fairfax County, where residents of Lorfax Heights, Laurelwood, Newington Station, and Windrush have altered their life styles, bought elaborate home security devices, and are "downright nasty to all stangers," as Messine puts it.

Many nearby residents said they were dismayed that an air-raid-style siren, installed at Lorton to warn neighbors of inmate escapes, was not used yesterday after four armed men who broke into the Lorton complex and gunned down an inmate fled into the surrounding area.

Fairfax County police spokesman Warren Carmichael said the department received several telephone calls from the people who were "perturbed" by the fact that they were not warned about the shooting.

Although Lorton officials, under pressure of a lawsuit, agreed in the mid-1970s to use the siren, a prison spokesman said yesterday the alarm was not sounded because the break-in did not constitute an escape.

"I keep my doors locked at all times anyway," Shipman said, "and a loaded gun and a mean biting dog, but there should have been an alarm sounded. We should have been informed."

If the alarm had been used, said 48-year-old Alexandria janitor Larry Bueller, a Lorfax Heights resident, he would never have stopped his car to pick up a hitchhiker at 7 a.m. yesterday morning on Hooes Road, adjacent to the Lorton facility.

"He looked harmless enough, just a kid really and kinda quiet," Bueller recalled. "I flipped on the radio long enough to hear about what happened. Scared me to death. I looked at him and he started looking at me."

Bueller then announced that he was stopping the car. His rider readily agreed and Bueller drove back home, forgetting, he said, why he had left in the first place.

Most Fairfax County officials, including Board Chairman John F. Herrity, said they felt the alarm should have been used and said they will press for changes in the alarm procedures.

It's clear that we have to broaden the definition of 'escape" to include incidents such as these," Herrity said. "We're not going to fool around with the safety of the people."

Fairfax County Police Chief Richard A. King said meetings "with appropriate D.C. officials" will be set up "to review current policies for notifying residents."

The alarm, located on a farm inside the facility, now is sounded only after police have been notified by hotline telephone of an escape and after a head count has determined the number and identities of the escapees.

"There wasn't any more need to use it this time than for sounding an alarm if a guy had knocked off the local Shell station," said Leroy Anderson, a Lorton spokesman.

"That's pathetic," said one 18-year-old Hayfield High School senior. "The system isn't taking care of the people. A family here was taken prisoner by an excapee once. And we live right across the street from the prison."

Messine said she would move if she could, "but the home is paid for. I can't afford to move and now I'm downright nasty to all strangers, even when I know I shouldn't be."

Mrs. Bertran Croushorn has a teenager and a smaller child who catch buses on Hooes Road, not far from the service station where two off-duty District policemen caught one of the suspects.

"They should have sounded that alarm so a family can know to look out for the children," said Croushorn. "And if we are notified, it's often about six hours after someone has escaped. That isn't soon enough."