one of the sillier lines from the torture sequence was gone by the time they filmed the scene
What was the line?
Dialogue is a tricky thing because on the one hand the writer (quite properly) wants to be entertaining and to craft memorable exchanges that people will enjoy and remember, but on the other hand such "movie dialogue" lines can quickly leave behind a sense of believability (and even if they're things that people might indeed say in real life, it's a question, as William Goldman puts it in Adventures in the Screen Trade, of "believing reality" - in other words, it doesn't really matter whether it's "realistic" or not; what matters is whether audiences will buy it).
Few screenwriters - I'm thinking that people like Mike Leigh may be exceptions - can get away with writing dialogue that sounds exactly like real people speaking. For one thing, the way real people speak is often boring and confusing, and certainly not conducive to slick storytelling on film - people talk, for instance, in (as far as movies are concerned) unacceptably longwinded or shortwinded fashion, umming and erring and leaving sentences in the air. Just try putting that sort of thing in a script - chances are it'll be assumed that you cannot write, even though what you've written may in fact be perfectly realistic dialogue.
On the other hand, polish your characters' dialogue up and it's easy to come across as someone peddling phoney wannabe-Tarantino "smart" lines that don't carry the tang of authenticity. There's quite an art to this business of dialogue, and, judging by many finished films, it's one that by no means all professional screenwriters have mastered. Thankfully, though, it's often possible for actors to "rescue" questionable lines, as seems to have happened with CASINO ROYALE.
