Tris cannot believe that Caleb would betray her. It gives her a headache.
Peter tells Tris that he has to take her to the showers. On the way there, they pas Tobias… who ends up grabbing the gun from his guard and shooting.
Tobias grabs Tris and drags her into a secret control room.
Inside, Tobias tells Tris that her execution is scheduled to happen in two weeks. That's when the factionless, the loyal Dauntless, and the Abnegation will storm the Erudite compound to destroy their computer. (Got that?)
Tris doesn't think she can make it that long. He kisses her, but it's still not enough to convince her. She thinks, "He is wrong, and I do not want to survive this" (32.59). That must have been a bad kiss.