Spoilers follow.
The Young Man (Jeremy Theobald)
The following is my explanation - well, rather an account of what happened.
- Covert Pervert: He and Cobb steal some of the Blonde's underwear during the theft of her apartment.
- No Name Given: He gives his name as both Bill and Danny, although he is only credited as "the young man".
Cobb (Alex Haw)
You're obviously not a policeman, so who are you, and why are you following me?
- Break-In Threat: Sometimes he doesn't take anything, he just ruffles through a few keepsakes, and makes sure people know it, to disrupt their lives.
- Even Evil Has Standards: He is reluctant to steal from anyone who seems to be a student, and/or an unemployed person. Could be subverted due to the movie being unclear as to which part of the argument "this person doesn't work, so he could go back home in any time" plays in the decision to leave quickly without stealing anything.
- Troll: He hides one of the Blonde's earrings just to screw around with her.
- You Have Outlived Your Usefulness: Towards the Blonde after he reveals that he is working for the Bald Guy and that he can't have any witnesses alive, which leads to her having her skull smashed in.
The Blonde (Lucy Russell)
- Black Mail: Toward the Bald Guy after she witnesses him committing a murder in her home, to which she has evidence in the form of a bloodstained carpet.
