Among the patients were newborn babies who had to be delicately evacuated.
Those at the hospital had never seen anything like it.
"We tried to call, the lines were down, tried to look at the website, everything was down, so then it was panic mode," Jennie Donovan said.
In October of 2012, Superstorm Sandy unleashed her wrath on the area, dumping an unprecedented 15 million gallons of water into NYU Langone.
The storm knocked out power to the entire hospital.
William is now 10 years old and has no recollection of the night his parents Jennie and Jeremy Donovan were forced to make a series of agonizing decisions under dire circumstances.
"Somebody popped up and said, 'hey are you Mr. Donovan,' I said yeah, he said, 'let's go,' we started running," Jeremy said.
When Sandy barreled in, William was just 21 days old and recovering from open heart surgery.
When backup generators failed, officials had no choice but to evacuate the hospital and move hundreds of patients, including the most vulnerable like William and other newborns, some weighing as little as 600 grams in the NICU.
"He had just become, the nurses call it wireless, when the storm hit, for the longest, he was on a ventilator and mediations, he was portable," Jeremy said.
After waiting outside for about three hours, a member of William's team spotted Jeremy. And up they went, climbing what seemed like an endless set of stairs and finally reached William's unit.
"It was our nurse Annie, holding William, she's like Mr. Donovan good, OK, lets go, we're going down," Jeremy said of the only way out.
Pediatric Cardiologist Dr. Achi Ludomirsky retraced the path he took that night. He explained a team of five was assigned to each baby -- one person cradled the infant, there were IVs if needed, ventilation by hand and step by step with only flashlights and cellphones to guide them all.
"This is a victory of leadership and teamwork because otherwise the consequences would have been disastrous," Ludomirsky said.
William is now in 4th grade and doing just fine.
The Donovans said what happened that night was one of the most harrowing experiences of their lives and they can't say enough about the nurses and doctors who stepped up to the plate and got things done.
"It's just a chain of miracles, kind of all throughout this process to make sure everybody got where they needed to go, we're so grateful the way things worked out," Jeremy said.
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