How we cite our quotes:
She took a deep breath, wondering why she was saying all this, lying to Shay when she didn't really have to. She should just shut up, get to the Smoke, and get it over with. But Tally found herself continuing. (23.55)
Tally finds herself lying almost compulsively. Why does she lie to Shay when she doesn't have to? We're really not sure—maybe she's lying because she wants the lies to be true? Thankfully, one person Tally doesn't lie to is herself.
She wondered how many other spies the Specials had blackmailed into looking for the Smoke, how many times they'd come close to finding it. She wanted to tell David what they were up to, but how? She couldn't explain that she had come here as a spy, or David would never trust her again. (32.46)
Here's the real kicker of Tally's status: she was sent as an infiltrator, so she could totally becomes double agent here and spill all she knows about Dr. Cable to David. Around this time in the book, she knows that's the right thing to do—but that would mean harming her friendship with David. So which will she betray: her desire to be close to David or the Smoke? (Answer: the Smoke.)
"You did this!" Her whole body writhed like a snake in its death throes. "Stealing my boyfriend wasn't enough? You had to betray the whole Smoke!" (34.47)
What's the worst thing that Tally does in the book? Shay seems to think that kissing David is almost as bad as calling Special Circumstances to destroy the town. Imagine yelling at a friend, "You killed my parents—and ruined my favorite shirt!" Those two things don't have quite the same importance. But that's adolescence for you.