I guess in case of emergency, they can create a massive traffic jam. Which will be helpful. Oh, did I mention that the UN, being its own country, has its own fire and police? Because they do.
And now ... THE COAST GUARD HAS ARRIVED. A cutter just pulled up in the East River. I guess in case the UN is attacked by Brooklyn. This is endlessly fascinating. I think the firemen are bored. They just went up on the ladder and turned their hoses on some boulders.