I'm thinking along the lines of the OC (not yet sure if it'll be male or female) being the motivational support or something along those lines. As I honestly can't see him/her doing anything super. She/He'd be the person told to stay inside the car when hell breaks lose but they'd stillgo out of the car and in turn do something stupidly lucky.

Now that I think about it I'm not entirely sure how my OC can help other than being insanely lucky. haha.