[Shelob]

Regardless of intent (impulse or calculaton) Legolas' firing of an arrow could only have the one result it did.

Assume that the instant Grima made a move to attack Saruman Legolas fired, then since Grima is so much closer to his target it's virtually impossible for Legolas' arrow to save Saruman (unless arrows that defy gravity can also move at virtually impossible speeds). Then if Legolas took even a second to judge Saruman and make a desicion then Grima is already 'that' much closer to his target and the arrow will need 'that much more time', so Legolas would probably shot only out of retribution, not prevention, at that point (I'm assuming he'd be able to tell the hopelessness of trying to save Saruman at that point)

I guess you could argue that the intent is more important then the outcome, but I think the more important question in that would not be "how does this show Legolas' character?" but "why was it done this way?". I know somewhere in this forum (I can't remember the thread, I saw it the first day I looked around this site...if you recognize this idea let me know where it is and I'll gladly give credit to whomever diserves it) someone suggested that they could have had a nameless soldier shoot Wormtongue instead of Legolas. To me that idea makes more sense and keeps it more within the spirt of the books.

Sorry if this is kind of long...I didn't relize it would be so much when written down.