News reports indicate that NYU had their generators on the roof, and they evacuated at least one day before Bellvue. So location doesn't matter that much.
When the plan isn't tested anything can go wrong. A hospital near Clear Lake City TX was carefully constructed with ER and surgery etc on the 2nd floor, with nothing needed for emergency operations below. And with the first tropical storm they learned that the elevators all had their control boxes in the basement and underwater.
As for the Comfort, don't count on it. It's big, unmanned, and a converted oil tanker, with only space for 1 helo.
.. and 1,000 beds, a dozen operating rooms, equipment & stores kept ready for deployment and a staff/crew that is supposedly kept on 5-day call-up status.
I don't know where it is, or if the crew was recalled.
And I bet Comfort is *far* cheaper to keep in NYC than whatever combination of warships they're sending.