Randy exchanges nods with the gunmen and goes into the building’s lobby, which is just as hot as outside. Bypassing the bank, ignoring the unreliable elevators, he goes through a steel door that takes him into a narrow stairwell. Today, it is dark. The building’s electrical system is a patchwork—several different systems coexisting in the same space, controlled by different panels, some on generators and some not. So blackouts begin and end in phases. Somewhere near the top of the stairwell, small birds chirp, competing with the sound of car alarms being set off outside.