A few years ago around Christmas as I went outside with some garbage I ended up standing unseen in the dark as two police officers were in discussion with an obviously disturbed man, on my quiet street, who was making threatening statements.  They engaged him calmly, from a distance , asking him questions about himself, what doctor he was seeing, who his case worker was, etc.  They made some light and sometimes humorous banter and eventually got the fellow to sit down and when the ambulance came, he was calm enough to get in.  These were two young white officers and the disturbed middle aged man was black.  I often think I witnessed what should be happening.  Drawing weapons and yelling at this fellow would have escalated him for sure.