Just re-read the first half (or so) of "A Fanfic Writer's Guide To Writing"

[hazard]

Regarding calling the emergency services; many of the people who answer those calls are either certified in first aid, training for that certification, or otherwise trained and prepared to talk you through providing first aid. They also will point the appropriate emergency service your way with all possible speed. And that may be just enough to make the victim survive, or not enough with the victim dying anyway despite best efforts.