According to Yahoo News, a driver in the UK got behind the wheel of an ambulance while paramedics were treating a victim in the back so he could park his Mini Cooper in a space that was being blocked. According to the paramedics, they didn't communicate at all with the Mini driver. The patient suffered "distress and discomfort" but was otherwise unaffected.
Unfortunately, police are still trying to find the driver. While we can't do much from Michigan, we can provide a brief description. The suspect is a white male with dark hair in his 50s that stands about 5 feet 10 inches tall. The Cooper had a license plate that starts with RJ60. If you have any information, call the police in the UK at 101 or Crimestoppers anonymously on 0800 555 111.