The young man became delirious, telling his mother, Barbara Skaggs, that he wanted to go to the smoking section even though he had never smoked. His blood pressure dropped.
Belken, a 20-year-old Marine, had been dealing with two potentially life-threatening conditions at once -- a recent onset of acute leukemia and a blooming infection from a smallpox vaccination. He was that unlucky one-in-a-million case, his doctors said, but one they hoped would end well.
Unfortunately, his immune system wasn't regenerating very well after two rounds of chemotherapy.
Belken was crashing.
In doctors' and family members' account of that harrowing night of March 7, hospital staff at Naval Medical Center San Diego scrambled to get Belken to the intensive care unit about 11 p.m. and worked on him for about 12 hours. Doctors pumped five medications called vasopressors into Belken's body at the highest dose, constricting peripheral blood vessels to keep blood pumping to his heart and brain.
Other organs started to fail. His hands and feet turned dusky.
On the afternoon of March 8, Lt. William Danchenko, an oncology nurse practitioner, approached family members in the waiting room. He thought this was it.
"We need you now," Danchenko told them.
Skaggs, 39, rushed to the bedside of her only child. "Come back," she begged.
Belken was the victim of bad timing, said Lt. Cmdr. Edith Lederman, an infectious diseases specialist at the naval hospital.
When a corpsman at the Marine Corps Air Ground Combat Center in Twentynine Palms, Calif., jabbed Belken's arm 15 times to deliver the smallpox vaccine Jan. 13, the young man felt fine.
He was running regularly and lifting weights every day. His family, which hails from the St. Louis area, had no history of leukemia, a cancer of the bone marrow that cripples the immune system.
His answers to a standard set of health questions did not rule him out from getting the standard regimen of vaccines for deploying to Iraq. So Belken got the smallpox shot, which delivers a live form of the virus vaccinia, a milder cousin of the smallpox virus variola.
Had the cancerous cells built up faster, officials would have seen the symptoms of leukemia and exempted him from getting the vaccine, Lederman said. Or, if he had gotten the vaccine several months earlier, she said, his immune system probably could have cleared the vaccinia without much trouble.
"It's a fluke, really," Lederman said.
More than 1.7 million service members have been vaccinated against smallpox since 2002 because of fears of a bioterrorism attack. Most simply develop a tiny blister that scabs over after 14 days. The scab typically falls off by the 21st day, leaving a barely visible circle of new skin on the arm.
But the military knows it is risking potentially fatal side effects to protect service members, who are exposed to diseases most Americans never encounter.
About 200 service members have developed complications associated with the smallpox vaccination that were serious enough to require hospitalization or absence from work, according to Lt. Col. Patrick Garman of the Military Vaccine Agency. Problems included inflammations of the brain and parts of the heart.