The next day, Tris seems a little low just because someone got stabbed in the eye. Some people are so sensitive about eye-stabbings.
To give her a pick-me-up, Uriah invites her to a Dauntless initiation rite. (Uriah is an initiate, like Tris, but he was born into Dauntless, so he knows all this inside stuff. But he was on her team during the paintball game, so he knows her even though the Dauntless-born initiates train separately from the transfers.)
The whole group of Dauntless, including Tris, gets on the train to go to the empty Hancock Building. Along the way, Tris meets and gets friendly with a few other Dauntless folk, like Shauna and Uriah's brother Zeke.
But who cares about that when the initiation rite is zip lining from the top of the Hancock Building all the way down to the ground? Which is a crazy long, fast, and high zip line (kind of like this one).
It's exciting and community building and Tris has a great time.
Except when she gets home, her old friends Christina, Al, and Will wonder where she's been.
And while Tris has been having fun with the Dauntless, Christina was arguing with an Erudite reporter. The reporter wanted some dirt on Abnegation, so Christina almost punched her. Like a good friend would.