
Other mistake: When Somerset goes back to the man's house alone, he cuts a sticker on the door with his switch-blade to get in. The first error is the sticker is on the inside and it says "Keep Out." The best part about it is the door opens inward. How did they put the sticker on the inside and then exit? (00:20:45)
Answer: Doe claims to represent the sin of "Envy" when he killed Mills wife; he was envious of Mills' normal life, and killed Tracy after failing to "play husband" with her. After that Mills kills Doe by shooting him repeatedly, becoming the embodiment of "Wrath".
Anastasios Anastasatos