DKI Jakarta - Jakarta Utara
I think you can just refuse to do the action, but once you rolled the die you started the action thus you need to finish it.
Yes, playing the card doesn't need you to activate the action, since actions (beside event symbol) is optional you can ignore it. But once you decide to activate the action, you are committed to it. You must remove the minion, even if it's yours. But if the region is empty, Carcer cannot kill.