It begins at South Tower of the World Trade Center, and as Burke enters an express elevator (Car 6 or 7 if you must know) he says in effect, "Do I worry about ascending to the top in a steel box? Of course I don't! We take going up in the world like that for granted." When an elevator later goes dark he says. "We expect this to happen sometimes so what do we do? We strike a light and look around in the dark for an emergency button to push and if we find one, we press it." In this discussion of single takes, note what the temperature of the butane lighter must have been by the time he finishes his speech. Ouch!
Also interesting to note in the realm of happenstance: the airliner portrayed in trouble over darkened New York was flight 911.