Acouple stepped out in tandem, holding hands. One man went headfirst, captured freeze-frame on film, arms loosely at his side, one leg akimbo in a graceful passe{acute}. A woman jumped while primly clutching her handbag, as though she might have to hail a cab when she alighted.

Among the most heartbreaking images in a day of haunting imagery were the dozen or more people who took stock of where they were and what was happening to them, and leapt. Some were on fire. Most were not.

Why jump from the 90th floor of a burning building, to certain death?

Possibly because they could.

"In a way, it was a healthy response," says Ronald Maris, a forensic suicide expert and director of the Center for the Study of Suicide at the University of South Carolina. "It is taking charge of a situation rather than letting the situation take charge of you. The primary motive of all suicides is escape. What are they fleeing from? In this case, they have escaped from terrible thoughts of being crushed to death, or burned to death, by annihilating their consciousness in a way that is nearly instantaneous."

In the 1911 Triangle Shirtwaist factory fire in New York City, more than 50 people jumped to their deaths from the ninth floor. The year before, nearly 20 people leaped from a burning tenement in Newark, N.J. In each case, some people survived, or survived long enough, to explain why they had chosen the window. Several said it was to make sure their bodies would be identified, and not incinerated beyond recognition.

"It's an issue of control," says Lanny Berman, executive director of the American Association of Suicidology. "All people want to have some control over their lives, and that includes the nature and timing of their deaths. The notion of having death happen to you is less viable than being in charge of it."

According to Maris, there have been cases of people about to jump off the Golden Gate Bridge when a police officer pulls up and says, "Get down or I'll shoot." Usually, the jumper gets down. He may want to die, but he wants to control how.

In this case, the issue of control may simply be choosing the less odious of terrible alternatives. Psychologically, there's no competition.

Says Berman: "People who have jumped from the Golden Gate Bridge, and survived, report that the fall was experienced as almost transcendent, that it went in slow motion, that the experience was almost mystical."

Maris says he can understand how the Trade Center victims must have felt, standing at the window. On one side of them was unbearable heat, and roaring flames, and acrid smoke, and screams of the suffering. On the other side, fresh air.

"Many years ago, I sat on a window on the 34th floor of a building in San Francisco with this 16-year-old kid who was thinking of jumping. We looked out, and it was very romantic, we could see the bay, we could see cumulus clouds. It was all beautiful, and jumping, well, it would seem a little like flying."

It is unlikely that at the moment of their decision, any of the jumpers saw beauty in their plight. Their decision may have been an effort to seek control, or to choose the better of two awful alternatives. Most likely, says Calvin Frederick, former UCLA psychiatry professor and an expert on traumatic stress, the choice was unconscious, impulsive, a reflex more than a decision.

"There's smoke, there's a fear of horrific pain, it's imminent," Frederick says. "You can't breathe, and here is an escape. Your response is very primitive. An animal response. You become a human animal at that point, and an animal will flee."

Years ago, Frederick says, a colleague of his set up an experiment where he subjected laboratory animals to excruciating pain. They could go into another chamber to escape the pain, but if they did they would get their heads chopped off. Other lab animals were allowed to observe this, so they knew what would happen. They they, too, were placed in the pain chamber. They leaped out of it, into the killing one.

"The urge to escape the pain," said Frederick, "overrode everything else."

Those who jumped may have sought some control over death.People trapped by fire and smoke look out the World Trade Center's North Tower. It would collapse minutes later.