Ok. I need your help on a Serenity deal.

PROFANITY 5 – 1 F-word, 2 sexual references, 3 scatological terms, 4 anatomical terms (3 mild), 12 mild obscenities, 3 religious exclamations.

Kids-In-Mind-.com, a pretty good resource for parents wondering about movie content, says that there was ONE F-bomb in Serenity…not in the extras, but right in the film somewhere.  I, for the life of me, cannot find this occurence.  Can any of you tell me when this is?  Its buggin me.