The scene can probably be trimmed to remove the needle altogether. If you cut away before the camera zooms over to the needle, Leia's reaction of horror should be enough to suggest that this robot isn't going to be good for her.
The idea of a needle isn't in itself so bad, as the torture device Han in put onto in Cloud City is full of needles, but the needle on the Death Star droid just looks like a syringe, and far too Earthly.