[Diamond18]

Oh, oh, oh, I know the answer to this question!<P>The script writing team (per se) had nothing to do with the whole stair sequence. In the script it still says "The Fellowship descend some stairs and reach the Bridge". Okay, not an exact quote, but that is basically all the script says. When the CGI crew got ahold of the scene, they were inspired by Alan Lee's conceptual drawings of the stairs, to make it seem more dangerous. So they added in the crumbling bits and toyed around with the computer models, making the animated characters do all sorts of stuff (even more than was actually in the movie).<P>PJ decided that what they had on the computer looked really cool, so that's how the movie turned out. So basically it was the SFX guys playing around with their computer program because when they looked at the steep, narrow stairs that Alan Lee drew, it made visions of narrow escapes dance in their heads.<P>My source: one of the pre-production documentaries on the 3rd Disc of the Extended Version set. Can't remember just which one, but it's there somewhere. And they even said that the script still reads that all they did was descend some stairs.