I think it was there mainly to poke fun at Gimli; here he was warning the hobbits and talking about his keen hearing and suddenly there are arrows in his face!
"arrows in his face!"
They always feel like they have to be dramatic in the extreme in movies anyway. Cars have to explode when they're wrecked, etc.
Come to think of it, in Long Kiss Goodnight, when they ran over a deer with a Volvo, even the Volve exploded, which was funny.