Life may have begun returning to normal for U.S. troops in Saudi Arabia, but that is hardly normal life. Strangers in a strange land, they had already been forced by the deepening threat of terrorism to retreat within a tighter and tighter security cordon. Now they face even greater restrictions. Hobbling on crutches, Airman 1/c Steven Byers chuckled bitterly over the letter he sent his brother a few days before a shard of glass driven by the blast tore open one of his knees. ““I told him how great it was here, with air conditioning and a pool,’’ Byers said. Troops now use a prison term to describe their new lifestyle: lockdown.

Saudi Arabia has been a hardship post for GIs from the day Saddam Hussein’s invasion of Kuwait compelled the king to accept a substantial U.S. military presence. The troops receive up to $250 extra a month in danger pay and other benefits, plus a total or partial holiday from federal taxes. And typically their tours are limited to 90 days. In deference to the ““hosts,’’ alcohol is prohibited, even on base, as are magazines that show any part of the naked torso–including fitness and fashion publications. Christian religious services, outlawed in the kingdom, are held secretly, with schedules posted in code.

A growing climate of menace has made the duty even bleaker. Troops who rotate in and out of the kingdom have seen security measures steadily ratcheted up. ““At almost every squadron meeting there was some mention of the threat,’’ said Capt. Jon Wolfe, an F-15 pilot whose last tour ended in April. Largely confined to base, he jogged six miles a day inside the compound. Others played softball and volleyball, generally under lights at night when the temperature dropped. The June 28 base newsletter noted that ““everyone must wear their dogtags at all times,’’ and security police advised Khobar residents, ““Close all window shutters and curtains and stay away from the windows … Remain inside as much as possible.’’ A four-stage terrorism THREAT LEVEL sign stands at the entrance to the complex beside the HEAT STRESS notice. At an orientation briefing, Byers recalled, ““they said we could go into town only in groups of two to four. They said the threat is always there.''

Then there were the strange doings in the large parking lot just adjacent to the tower known as Building 131. Saudis often used it to practice driving, and the lookouts grew accustomed to watching hapless learners hit the light poles. But there were more sinister incidents as well, when people would park for a few minutes in front of the compound fence. ““We had a feeling that we were being watched,’’ said security policeman Alfredo Guerrero. Some residents, conscious of their vulnerability to a car bomb, considered moving into their offices. ““Our building was a prime target,’’ says Staff Sgt. Anthony Overvay.

Guerrero was visiting an observation post on the roof of Building 131 at 10 p.m. Tuesday when he noticed a tank truck and a white Chevrolet Caprice pull up to the perimeter. The truck parked so close to the fence that he could hear it scraping against a hedge. And the two terrorists jumped into the car, which sped off. Guerrero says he had little doubt that it was a bomb. He radioed a warning to headquarters and ordered two other policemen with him to help evacuate the building. ““I saw my life flash before my eyes, and I just wanted to get out of there,’’ says one of them, Airman Christopher Wagar, 20. ““But [Guerrero] reminded me about the other people.’’ Pounding on apartment doors and shouting ““Incoming!’’ they had reached the sixth floor of the eight-story building when the massive explosion hit, 3i minutes later.

The carnage shocked rescue workers. The blast wave inflicted gruesome trauma on those it killed; more than half a dozen bodies were so badly mauled that identification was impossible before they were shipped home. A jogger who had been passing the building was literally blown out of his sneakers and killed. Tears ran freely as the corpses were removed from the rubble, said Staff Sgt. Jim Tyson, a military mortician. One soldier who had officiated at a weight-lifting competition earlier in the day retrieved the body of one of the competitors. ““This was done by cowards,’’ said Tyson, his voice breaking.

““I tried not to look at the faces,’’ said air force medic Jason Call, who gave first aid to victims at an overwhelmed clinic in the Khobar complex. A courtyard between the clinic and a base chapel became an impromptu triage center. One paramedic showed up covered in blood from multiple cuts; he ““went and morphed himself up and [pitched] in,’’ said paramedic Andrea Richards. Air force practice of first-aid drills, called Self Aid and Buddy Care, helped keep the death toll down. ““There wasn’t a single patient who arrived at the clinic who was not bandaged up already, and often splinted, either with bandages or with bedsheets and T shirts,’’ said the doctor in charge of triage, Lt. Col. Doug Robb. Some 450 Americans and Saudis were treated; by the weekend, all were out of danger.

The blast won’t stop the troops from making the most of life inside the perimeter. Thursday night is party night at Khobar Towers, and last week was no exception. Most of the action was at the base’s recreation center, dubbed The Konnexion. Men and women in casts and neck braces, with bandaged limbs and swollen faces, danced to country music or watched video movies, played pool or sat drinking near-beer. Senior Airman Tanya Burford, 22, of Hueytown, Ala., was hobbling around between dances; her legs were badly cut in the blast. ““We go slow, that’s all,’’ she said. ““When you’re over here for so long, your Saturday night is so special. We’re trying to go on with business as usual.''