EMS and other emergency responders rescue residents by boat after a levee break devastates three towns.
Paramedics and other medical workers evacuate patients from NYU Langone Medical Center due to a power outage caused by Superstorm Sandy.
First responders called into action as city plunges into darkness.
Governor outlines emergency response, emphasizes storm's intensity and long duration.
"This is not a coastal threat alone," says FEMA director.