One extra point to make, which I only learned when I met a paramedic who worked at several police stations over a wide area (at my place of work, not his, I hasten to add!) is that while Police will inform a HCP of need for an assessement visit, it can take a while for the HCP to drive to the station; the procedure then needs to be repeated for each blood test and each insulin injection, with the aim of preventing any self harm - may sound unlikely, but deaths / suicides in custody are sadly not unknown.
While it's very unpleasant to have high blood glucose of around 17, as you quote "At the hospital the doctor said that I wouldnt die by having high blood sugar!" I'm not clear when you got to the hospital? After leaving Police station? Some time later when you enquired about treatment? And remember, alcohol does bring down blood glucose - as you noticed by being hypo when you left the Police station at 3am with your cereal bar.
Were you actually arrested? Or taken into custody after being checked at hospital - A&E departments need to keep the situation for staff and other patients and companions safe, and sometimes that means getting Police to remove drunk people to a place of safety.
Not a nice situation for you or anyone else involved, SONIC. Hope you manage to find out what happened, when etc and complain if your treatment doesn't match Home Office guidelines, not just relating to diabetes, but access to lawyer and telephone call.