Cut their own throats - Idioms by The Free Dictionary
cut (one's) own throat (redirected from cut their own throats)
cut (one's) own throat
To cause problems for oneself with one's own actions (which are often motivated by anger). I know you're mad at your dad, but don't cut your own throat here—running away is only going to make your life harder.
cut your own throat bring about your own downfall by your actions.
cut your own ˈthroat do something that is likely to harm you, especially when you are angry and trying to harm somebody else: You cut your own throat when you told him to leave. How are you going to manage alone?