I hope they were collected, or got a cab home, then came back for the car the next day.
Having watched the highlights video, I'm more minded to think the referee called the red card correctly. It looked little more than a coming together at the time, and the referee (sensibly) took a fair while to consider his decision, but Mills was clearly goalside and got brought down from behind. If you don't think he's a serious threat why bring him down? The fact we converted a direct free kick from that position also suggests it was a goalscoring opportunity!