In the climactic scene of the movie, Gittes tries to help Evelyn escape to Mexico. Gittes confronts Cross with the glasses, and he actually thinks that Cross will somehow be defeated. But Gittes is immediately shut down. Polanski’s point is that we should accept Cross’s power as total and inevitable. Therefore we should accept the film’s conclusion as equally inevitable. The opening moment of the scene suggests Jake has outsmarted Cross because when he gets out of the car, he leads them right to his guys. Then a shock. Escobar is there and Jake's guys are handcuffed. Jake is again relieved when Escobar arrests him because it means he's escaped from Cross. Jake tries to explain everything, but Escobar handcuffs him and won't listen to him. Escobar is convinced that Evelyn is the killer and Jake helped out. Jake frantically tries to explain that Cross is the one behind all the killings and the water/land plot, but Escobar is beyond trying to understand him. Polanski successfully shows human corruption through the final scene. In the end, nobody seems to know the meaning of what they've just seen and experienced. But Jake knows better. What he has discovered is that it's not just in Chinatown that you can't know what's going on. It's everywhere. Noah Cross's evil and Evelyn's tragic inheritance did not happen in Chinatown, but in the richest areas of Los Angeles. What Jake's so painfully learned is that Chinatown represents the whole world, and how corrupt it's become.
Polanski successfully shows human corruption through the final scene. In the end, nobody seems to know the meaning of what they've just seen and experienced. But Jake knows better. What he has discovered is that it's not just in Chinatown that you can't know what's going on. It's everywhere. Noah Cross's evil and Evelyn's tragic inheritance did not happen in Chinatown, but in the richest areas of Los Angeles. What Jake's so painfully learned is that Chinatown represents the whole world, and how corrupt it's become.