At the start it's Joo-yun's, as discovered by the police, severed by Kyung-chul, and at the end it's Kyung-chul's, as discovered by his own family, severed by a trap set up by Soo-hyun. Bookends: The film's main plot begins and ends with the discovery of a head.When Tae-joo tries to remove the screwdriver pinning his hand on the table, the handle promptly comes off with a humorous "pop!" He slams the table in frustration.He rummages around behind his seat muttering to himself while his future victim watches him in confusion. While preparing to murder a woman he's given a ride, Kyung-chul misplaces his murder weapon.Big Bad: Kyung-chul is the psychopath whose being at large while committing murderous acts sets the story in motion.All of this is part of what makes Soo-hyun's catch-and-release plan so reckless. The only reason he relents is because he turns his attention on the doctor's attractive nurse. Even after getting his hand mended by a doctor, he nearly decides to murder the doctor over some gentle scolding. Ax-Crazy: Kyung-chul reveals himself to be a danger to just about everyone around him.Asshole Victim: The two crooks in the taxi plan to rob and kill Kyung-chul, who figures it out and kills them both.At one point he lets Kyung-chul rape someone long enough just so he could disrupt his enjoyment that much further. Anti-Hero: Soo-hyun, who doesn't seem to care that his plan for revenge also puts innocent bystanders in danger.However, once he leaves Kyung-chul holding up his own guillotine blade by a rope in his teeth that connects to a door, his family arrives and starts to open the same door, at which point he begins letting out very real, very terrified pleas for them to leave. When Soo-hyun finally gets Kyung-chul exactly where he wants him to execute his final act of revenge, he seemingly breaks down and begs for his life, but then drops the act and states that since he cannot feel pain or fear - the exact things Soo-hyun wants him to feel the most - Soo-hyun's work is All for Nothing. Ain't Too Proud to Beg: Double subverted.One has its Achilles tendon cut, another steps on a fishing hook.
Agony of the Feet: Both of Kyung-chul's feet.
This movie provides examples of the following: