Reminder that in many jurisdictions, not acting when someone is in danger is a crime that can get you arrested. You *have* to act if you're aware a friend is going to kill themselves, or cops will build a narrative against you, and at worst you could be literally convicted of involuntary manslaughter.
I'm not saying "tell the cops if your friend is having a mental health crisis". Calling an ambulance is one of the best things you can do.