Weapons that go “zzzzzzzt” aren’t as personally satisfying as weapons that go “Boom!”, in my opinion.
It depends. Having a mortal enemy disappear utterly, leaving nothing but the crackling end of a shoe-lace, is not only cleaner, there's less to have to explain.
Just pick up the remaining evidence by the aglet, drop it into a wastebasket, and turn with a mild expression when the officials inquire, "What's going on here?" and say:
"Oh, nothing Officer. Everyone here gets along just fine."