It isn't until she hits the third sandwich that Kamala finally slows down. She's finally feeling better. It's like she can properly breathe again. Kam might have relaxed then and there if not for that comment. "Duh! I always tell you the truth, Pete." The teen states like it's obvious. It isn't even really that she lies to her friends or family. He's just easier to talk to about all the stuff she buries deep. That's all.