David and Tally go to his parents' cabin, which is burned out. Tally checks it out, and luckily his parents aren't there.
Unluckily, when David goes through, he finds his dad's favorite knife, which means that the Specials caught his parents. If Az had gotten away, he totally would've taken his favorite knife.
David even tries to cut off the plastic handcuffs that Tally has (both sets), but the plastic is some superhard fantastic material. So now she has to lie about how she cut the middle part of the handcuffs.
Also, luckily, David's parents have been putting together an escape kit for him—dehydrated food, hoverboards, etc.—so they can travel to the city and rescue everyone. And then everyone will be happy and no one will be mad at Tally for betraying the Smoke.