The Question and Answer section for Divergent is a great resource to ask questions, find answers, and discuss the novel.
She feels as if the train whistle is the Dauntless calling to her. (Page 30)
The climax occurs when Jeanine attempts to take over the Dauntless faction. The trainers are instructed to inject all initiates with a simulation, thus, they are turned into droid-like beings that are completely under her control.
Beatrice is most irritated by Caleb's natural goodness and inborn selflessness.