''One minute, everyone was casually walking; next there was this huge surge,'' said Mr. DeAndrea, who works in an office beside the Trade Center. ''It seemed like 10,000 people were rushing toward us, running like a herd of gazelles, crying, 'Get out, get out!'

''It was so unreal. ''People were jumping out of buildings. It was horrifying.''

Frantically, Mr. DeAndrea tried to call his wife, but his cell phone wouldn't work. So he joined the surge heading back toward the ferries to New Jersey. At Pier 11, he said: ''Boats were just filling up, taking everyone. Some people were threatening to jump into the water if they couldn't get on.''

Finally, the overloaded boat pulled away. ''It was so scary. Everyone on the boat was just staring at the buildings. And then, as we passed the tip of Manhattan, they were there no more.''

The city looked and felt like a war zone Tuesday. Armed guards patrolled outside government buildings. Mass evacuations sent ash-covered pedestrians streaming across bridges. Ambulances screeched through Manhattan. A city skyline - and psyche - have been forever scarred.

At a triage center in lower Manhattan, Police Officer Tyrone Dux paused before heading back to the horror. ''New York is crying,'' said Officer Dux, himself in tears.

He was taking a break from shuttling medical supplies from St. Vincent's hospital to triage centers near the scene of the World Trade Center collapse.

''It's like nighttime there,'' he said of the scene in lower Manhattan, which by early afternoon was a hive of rescue efforts. ''I didn't hear any screaming, just dead, dark silence. ... Dark. Frightening.''

After the initial shock, after the nightmarish scenes of people on fire jumping from buildings, came the rescue.

A few blocks away from the World Trade Center, about 120 doctors and people with medical training traveled in a convoy of pickup trucks, ambulances, a dump truck and SUVs toward the wreckage. Their job: to find survivors and try to save them.

Paramedics waiting to be sent into the rubble were told that ''once the smoke clears, it's going to be massive bodies,'' according to Brian Stark, an ex-Navy paramedic who volunteered to help. Ad hoc medical crews formed to accept blood donations.

Barbara Kalvig raced to a triage center with a car full of colleagues from the New York Veterinarians Hospital. ''We closed the hospital and brought a bunch of doctors and nurses,'' Ms. Kalvig said. ''We just drove as far as we could.''

Nearby, a construction crew hauled two-by-fours and plywood to the emergency teams to be used as makeshift stretchers.

Craig Senzon, 29, a neurologist volunteering at the triage center said of rescuers, ''We felt a heaviness inside us that none of us have ever felt before.''