Clingy Jealous Girl: Though Evelyn helps John procure his young, female victims, she can't stand the thought of him actually preferring them over her, who has aged out of his bracket.
When she's allowed to write a letter to her family to stop them from searching for her, she codes what she believes to be their address into her message.
Chekhov's Skill: Vicki and her boyfriend send simple coded messages to each other.
He shows up at the end to collect his money, and though he doesn't discover Vicki, he coincidentally holds the door open as Vicki's family arrives so she can hear them and realize they're just outside.
Chekhov's Gunman: John meets his drug dealer at the corner store, who threatens him over his debts.
Fortunately, the Chekhov's Gunman allows her to hear her mother screaming her name, which rallies her strength and courage enough to stand up to Evelyn and survive. but since Evelyn steals mail, Vicki coded the wrong address, and they end up across the street, unable to find her. Right when Vicki's spirit is completely broken and she's ready to die, her loved ones decode her message and show up at the address. She does her best to stay upright, but a vicious (offscreen) rape and torture session from the couple breaks her spirit so much that she's ready to die, forced to take pills by Evelyn and writing out a final faked letter to her loved ones, claiming she's in another city.
Break the Cutie: Vicki is put through hell.
When she sees a picture of the family together in her diary, she becomes heartbroken and rips her mother out of the photo. As such, she has no interest in spending time with her or respecting her authority. Vicki loves her father and isn't truly a brat, but she resents her mother for what she views as abandoning the family.