If people are in crisis they have already lost their autonomy.
Says who? You should defer drawing that line to the experts; who will likely agree with 2xsaiko. Not being able to perform your job or blend in with society is different from being a threat to others.
We're talking with exception to people who don't threaten themselves or others. Themselves being the gray area.
Of course you would only focus on people having a psychotic breakdown where they threaten others, but having a mental health crisis does not mean someone is automatically a threat to those around them.
Here's a guide to de-escalating various mental health crisis situations.