Maggie Q: Watch Your Language!

Watched Mission Impossible 3 the other night. The funniest moment in the film was when Maggie Q, having just "accidentally" spilt red wine all over Philip Seymour Hoffman's white tuxedo shirt, blurts out: "ngo ho lun chun ah!" in what's supposed to be Cantonese. Cantonese has got at least 7-9 different tones per sound, each meaning totally different things. In the context of the film, Maggie Q, speaking in the correct tones, would have been saying she's really clumsy. What came out instead, very clearly I might add, was: I'm so f*&@ing dumb!

How could all the translators miss that? Or was it Maggie Q or some scriptwriter's inside joke to all of us Canto speakers??