It was the white noise of the helicopter blades slicing through the air - not the incessant emergency vehicle sirens - that tipped me off that something was wrong. In New York, the chaos - the wailing of an ambulance, the incessant honking of the horns - is so commonplace that it becomes an unnoticed, repeating chorus. Which is why when I heard the sounds of fire engines and cop cars while sitting on the 14th floor