Have them surrender. Have them try to flee. Have more enemies show up. Have the last couple bad guys fall off a cliff. Literally anything else. Never just "call it" that's the most lame way to end a combat ever.
If you're unsure an item is too powerful, make sure it has a limited number of charges and don't give it that dumb recharges at dawn crap. Then when it's all used up, the problem goes away.