generators were out of date and at risk before the storm hit. abc's david muir was at the hospital as the evacuation began. >> reporter: when we arrived, all you could see was the outline of the hospital against a darkened sky. a lone flashlight in one of the hospital rooms there, as doctors and nurses rushed from patient to patient. out front, ambulances, images from my iphone as we approached the hospital. just one of the nearly 300 patients who were one by one brought out and taken to safety. from the sky, ambulances lined up around the block from all over the city. and we're learning more about the moment the lights went out, the moment the critical machines, the respirators stopped. this young doctor right there. >> the patients on ventilators. >> the babies. >> babies, yeah. >> reporter: their first concern, babies in intensive care. 20 of them. this nurse clutching a newborn wrapped in a blanket holding one of those plastic bags. she was doing the work of the respirators herself. in fact, all the nurses in the unit were doing what's called bagging the air.