Yep, came across a man standing in a crosswalk in Berkeley who appeared to be dazed and the people with him asked me to call for an ambulance, explaining that the man had been pushed and hit his head on the street. It was probably within two minutes of my calling 911 that an ambulance had arrived and the man was being treated.

The other time I called 911 from roughly the same location, the call only rang. I hung up after probably 10-20 rings. [I woke up to the building next to my windows engulfed in 15+ foot flames. I setup the call while evacuating, but cancelled it once we began leaving the building. Made it outside and there were already many engines deployed and actively fighting.]

The non-answer is actually an issue common to 911 centers. A large, visible event happens (like a giant fire), and they get flooded with calls, all reporting the same thing.

With automatic location detection of many callers today, I wonder if the 911 services can play an automatic recording for callers identified calling from a hyper-specific location. Then many people calling from the same location about the same incident will hear a recording that tells them "X incident has been reported and is being responded to, press any key or hold if you are calling about another incident".