"You sort of get geared up to go do battle," says Bessey, associate director of the burn unit at Weill Cornell Medical Center in Manhattan, which has accommodated the most severe of the attacks' burn patients.
"It's really quite different than other times we've been busy. It's a siege. The thing about this is just this whole incident. We, as individuals, were affected just as much as everyone else in the country. This is our hometown. We have a close relationship with the firefighters, many of whom are now dead."
Bessey says the shear number of victims in need of treatment outdoes anything he has seen previously.
"Usually you get a patient with a big, serious burn once every two or three weeks at the height of the season," he says. "We had a dozen or more of these very critically ill patients at once. They usually come in one at a time. Having this many, this sick, all at once was a big stress factor for us."
Terrorists hijacked four airplanes Sept. 11, flying two into the 110-story Twin Towers in lower Manhattan, another into the Pentagon in Washington, DC, and a fourth, apparently headed for another target in Washington, into an empty field in Pennsylvania.
Following the New York attacks, 15 severely burned patients were admitted to the Weill Cornell hospital. The first of these victims, Manu Dhingra, 27, who Bessey says was burned over 40 percent of his body, was released Tuesday. Nine of the remaining 14, he says, are still in critical condition and on "complex life support," burned on up to 80 percent of their bodies. The other four patients could be released as soon as Thursday.
St. Vincent's Hospital, situated near Ground Zero, saw 681 injured people in the attacks' immediate aftermath, a hospital spokeswoman said. Of those, 113 were admitted to the hospital, most suffering from smoke inhalation.
The 568 patients not admitted were treated for broken bones, bruises and scrapes during the 24 hours following the attacks and released.
As of Wednesday, the spokeswoman added, only one victim of the Trade Center collapse remained in hospital, having had their legs severely smashed.
No one from Bellevue Hospital, which also treated attack victims, was available for comment.
Bessey says the vast majority of the burns he has treated in the attacks' aftermath have had "full thickness" (third degree) burns, where the fire kills the entire depth of the skin, from top layer to bottom.
To prevent infection, he said, this dead skin must be removed and replaced with healthy skin from elsewhere on the person's body, membrane from a cadaver, or an artificial, skin-like material.
"Each (victim) has already had several operations where we've removed the burned, dead skin," Bessey says.
Bessey cannot count the number of surgeries he has performed since Sept. 11, though he says it must be dozens, adding that the burn unit's attending staff has tripled both its hours and its nursing staff since the attacks.
"We went from a time when we would have one operating room operating three days a week, to two O.R.'s five days a week," he says. "I'm a little sleep deprived."
The patients range in age from Dhingra, who is 27, to another who is 59. Bessey says most of the burns he has seen are on people's backs and scalps, indicating that the fire caught up to them as they ran from its scalding clutches.
Bessey is careful not to be over-optimistic when offering prognoses for those patients remaining in critical condition, but says some have already beaten the odds.
"You really have to take a statistical approach," he says. "Based on the history and the size of the burn and the age of the patients, we expected when they came in that about half would die. We've lost two, only, since then, and they died of overwhelming lung failure.
"With the others, we would expect four to five to die, though they are responding to therapy."
Among those killed in the attacks, Bessey said, was a firefighter he had treated several years ago for serious burns over half of his body.
After his recuperation, the fireman rejoined New York's fire department and was promoted to captain just a week prior to the terrorist attacks.
"We have our own grief and anger," Bessey said.
Above all, Bessey says, is the tremendous feeling of unity he has experienced since Sept. 11.
"It is amazingly touching," he says. "We are grateful and touched by the tremendous outpouring from around the world. We in America are not used to being in this kind of position. When the chips are down it's really nice to know you've got friends all over the place."