I need help with this sentence:
Eventually it was Nick who pleaded with my parents to let their vice-grip go.
Context: A girl is going through a very difficult situation and after staying at her parents' for a few days (just for emotional support) she's now leaving to go back to her place and go on with her life.
I understand the meaning of grip, but I don't know what nuance vice adds. Has it got to do with the fact that it's two people holding her? I just don't get it . Any suggestions will be greatly appreciated!!!