I agree with
@Neonatal RRT, emergency services tend to have training best suited to crisis situations and are mostly concerned with solving situations in the most expeditious method possible. The issue is, when your only tool is a hammer, every problem begins to look like a nail. So if you were manic and were talking to everyone in the street and someone became worried about it and called 911 you could get emergency service responders swooping in and making the situation worse.
Things have improved a little in modern times and police etc should know when to carefully and diplomatically make sure they get mentally ill people to the appropriate mental health providers. But in the past, mentally ill people may have been arrested, put in cells and suffer violence.
It's a lot less prevalent these days but sadly you hear about mentally ill people dying in cells after being bull dozed by several enthusiastic police officers attempting to subdue them.
Fortunately for me, mania has usually been mostly just having high energy and trying to achieve more than is sensible, though there have been rarer episodes where I've been suffering delusions and having very wonky thoughts. If I had found myself surrounded by police I would probably have freaked out.
I think emergency services are really there for when you are in a severe crisis where you are a risk to yourself or others. At least in those sorts of situations the police etc may have more applicable training.
In the UK we have local Crisis Teams who can be called when you are worried about your safety. In my experience they can be a bit hit or miss. Some have been good, others not so much. But it may be worth trying to find out if there are any services that could help you if you need it and storing their numbers on your phone or card to keep in a wallet or purse so you have them handy.