If Dean knew what he was driving into, he would've let Jo get herself home. He loved her, but drama involving two girls was not the sort of thing that he'd go into willingly.
He'd gotten Jo's text and wasn't doing much, except wondering what the hell had happened to Sam, so headed out to pick her up. The Impala rolled up next to Jo and another girl, whose face Dean couldn't see. He parked her and waited.