The rapid rise of flood waters that overwhelmed emergency generators forced New York University (NYU)'s Langone Medical Center to evacuate some 260 patients overnight as New York City was being pounded by Hurricane Sandy. According to CNN, water began to pour into the basement, lower floors and elevator shafts of the hospital at around 7:30 p.m. Monday.

"Things went downhill very, very rapidly and very unexpectedly," said Dr. Andrew Brotman, the hospital's senior vice president and vice dean for clinical affairs and strategy. "The flooding was just unprecedented."

Hospital staff made the decision on Monday not to fully evacuate the hospital as it did ahead of Hurricane Irene in 2011 because flooding associated with Sandy was not expected to be as severe. The medical center was equipped with emergency generators, but as the lower reaches of the building filled with water, 90 percent of the emergency power was lost.

With power out, the machines keeping patients alive began to fail. Four newborn babies on respirators had to be carried down 9 flights of stairs to waiting ambulances, each one in the arms of a nurse charged with manually pumping the airbag on its tiny breathing mask. Patients from Intensive Care and other units had to be carried down as many as 13 flights of stairs before being whisked away to other facilities in a process that ground on through the night, with 40 patients still to be evacuated at 9:00 a.m. on Tuesday.

Brotman described the effort as "a labor-intensive, extremely difficult process" involving some 1,000 staff members, including physicians, nurses, residents and medical students. With only 10 percent of the lights in the hospital still burning, most work was done by flashlight overnight.

"Everybody's digging in and doing what they have to do," he said.

Watch video about the evacuation, embedded via CNN, below: