How is Nick taken hostage in Chapter 11?

In Chapter 11, Nick stops for coffee en route to the Academy. Coming out he sees a homeless man and gives him a dollar and a cigarette. The homeless man puts a gun in Nick's back and directs him to a limo. Nick walks to the limo, then spins on the homeless man and throws his coffee at him. Unfortunately, the coffee lids do not come off, and Nick is dragged in to the limo, where he is hooded and his hands are tied.