Infernal Affairs is a 2002 Hong Kong crime-thriller film directed by Andrew Lau and Alan Mak. It tells the story of a police officer who infiltrates a triad, and a police officer secretly working for the same gang. The Chinese title means "The Unceasing Path", a reference to Avici, the lowest level of hell in Buddhism, where one endures suffering incessantly. The English title is a word play combining the law enforcement term "internal affairs" with the adjective "infernal". Infernal Affairs was followed by Infernal Affairs II and Infernal Affairs III. Wikipedia
Chan Wing Yan: Should I salute you? Lau Kin Ming: No, don't. How long have you been an undercover? Chan Wing Yan: I've followed Sam for 3 years; I had several other bosses before. All together, it's been 10 years Lau Kin Ming: 10 years? I should salute you, instead. Chan Wing Yan: I just want an identity. I want to be a normal man. Lau Kin Ming: Getting tired? Chan Wing Yan: You've never been a mole. You won't understand. Too bad I still can't find the stooge. I'll take him down if I've found him. Lau Kin Ming: Don't worry. Let me give you back your identity, I'll open your file, but I don't have the password. Chan Wing Yan: What's the Morse Code for undercover?