I got to admit, when I read the book I was startled to see that word on there. I think it helped drive the point home though. Mal wasn't angry, he was livid. Seldom do any of the character curse in english, and most Chinese phrases don't seem to be very bad (some even being a bit funny.)

I think the look on Mal's face and his body gestures during that scene did a good job of showing the level of anger he was at. The f-word word works well in the book because we can't see the intensity of Mal's emotion. You’re left thinking, "Wow... I don't remember ever hearing Mal say that. He’s gone beyond angry.”

People, who don't yell, scream or cuss often, get the most reaction when they do. That’s what made Simon's reaction to the statue of Jayne (in "Jaynestown) so great. Especially considering the discussion he and Kaylee had just minutes earlier. He didn't cuss when Jayne trashed his infirmary, although he did call him ‘a trained ape… without the training.’ But him saying, ‘Son of a bitch!’ at the sight of a statue of Jayne in the middle of Mudderville was priceless.

Of course Jaynestown was a funny episode of Firefly. In this scene in Serenity, Mal is getting pushed into a corner and resorting to a rather “unspeakable” tactic that wasn’t sitting well with his crew. But Mal wasn’t going to argue the point with his crew or anyone.