Found another little slipup of either Jim himself or an oversight of his editor. Happens just before chapter 28 and shortly into it.
The power is out because of Cowl, but after Harry is done talking to Billy he As I rode down in the elevator, I had to admit that Billy might have a point.
Except a little bit later at Shiela's apartment: ...before I realized that, duh, the power was out and I wasn't going to be able to ring her apartment.
Very interesting, unless elevators run on coals in Chicago, and are uneffected by a black out.