The three young women chatting behind the ground-floor window of a Beirut newspaper office seemed to sight the gray blur of the approaching car at about the same time. They jumped to their feet and fled toward the door . . . only to discover that the car's driver was an old friend who had parked on the sidewalk in front.
In Beirut, which has known almost all variations of violence in eight years of civil strife, this is the season of the suicide car bomb.
This, at least, is true of west Beirut, the largely Muslim sector where most foreign missions and various government offices stand. The Christian east lives with its own special fear: shellfire from rival Druze militia positions in the hills above the capital.
Vehicles packed with explosives drove into, and devastated, American, French, and Israeli military headquarters in Lebanon this autumn.
The city, in character, has wasted no time in adapting to the new danger. An odd collection of preventive steps, from the improvised to the ingeniously intricate, has given the streets of this onetime Mediterranean tourist mecca the appearance of a cross between an obstacle course and a series of bunkers.
At least until last week's murderous explosion at a civilian apartment complex in west Beirut, the countermeasures focused on political and military installations. Some examples: the Lebanese prime minister's office; United States, French, and Italian diplomatic or military missions; and, of course, offices and installations under control of the Israelis, who invaded Lebanon last year and remain here.
Italy, the only major partner in the multinational peacekeeping force so far to have been spared a suicide bomb strike, has, for instance, fortified its embassy just off west Beirut's most chic shopping thoroughfare, Hamra Street. An enormous barrier of oil drums packed with sand and stones nearly hides the mission from view. A few blocks away, a similar line of defense fronts the Lebanese premier's office.
The Americans and French have closed the roads in front of their respective embassies in west Beirut to all but official vehicles. Intricate checkpoints force even these to snake back and forth in approaching the US mission - moved to the nearby British Embassy after a car bomb last spring wrecked the old American Embassy - to prevent cars or trucks from gathering too much speed.
The Israelis, both in their ''liaison office'' near Christian east Beirut and in south Lebanon, have adopted similar measures. Israeli personnel also routinely keep a vehicle of their own parked in front of some installations as a barrier of last resort.
On other Beirut streets, shops, official bureaus, and newspapers have improvised other precautions. Concrete blocks, metal spikes, and the long-preferred sandbag barriers are among the most widely used.
Still, there is an air of dolorous resignation in Beirutis' talk of such steps, a sense that the suicide strike may be ultimately indefensible.
Residents of the area near the US diplomatic mission, for instance, are occasionally awakened by the growl of a huge city garbage truck scooping up piles of street refuse not far from the British Embassy's new defense perimeter.
''Maybe I'm getting paranoid,'' a neighborhood man says, ''but I can't help shuddering at the nightmare of explosives buried in the truck's load. . . .''
Such fears redoubled with the car bombing early last week in a west Beirut residential area. Older-style tactics were apparently used: The car was simply parked in front of an eight-story apartment block. Dozens of civilians, including young children, were killed or injured. Beirutis wondered aloud whether this attack signaled that everyone, not merely foreign missions, was now deemed fair game for the terror strikes.
The fear persists. It is made only a bit less jolting by the subsequent theory among Beirutis that the vehicle was being prepared for a suicide strike somewhere else and exploded prematurely.