I always wondered about the point of this app in the U.S. In general, emergency services here are quite good and if I call 911 in an emergency, someone is going to respond pretty rapidly. Seems like the business might actually be useful in a place with low/no emergency service infrastructure where citizens or private security may actually be the only ones to respond (also, some interesting models for e.g. very crowded/congested areas for trained first responders to give emergency help like CPR to someone while an ambulance is on the way)