Short answers, pulled from the story.
EMS stands for emergency medical services. EMS agencies provide urgent pre-hospital treatment and stabilization for serious illness and injuries, then transport patients to definitive care such as a hospital emergency department. They may also operate non-emergency patient transport and some run rescue or search-and-rescue teams.
Dominique Jean Larrey (1766-1842), Napoleon Bonaparte's chief surgeon, designed the first organized ambulance system. His ambulances volantes, approved by the Committee of Public Safety in 1794, were horse-drawn wagons that retrieved wounded soldiers from active battlefields rather than waiting for fighting to cease.
The first known hospital-based ambulance service in the United States operated out of Commercial Hospital in Cincinnati, Ohio, by 1865. Bellevue Hospital in New York launched a similar service in 1869, stocking ambulances with splints, a stomach pump, morphine, and brandy.
The Anglo-American model, called load and go or scoop and run, transports patients to hospital as quickly as possible with paramedics and EMTs providing stabilization en route. The Franco-German model, called stay and play, dispatches physicians directly to the scene to deliver advanced treatment before transport, with the goal of stabilizing patients on site.
The Golden Hour is a North American trauma care theory holding that a victim's best chance for survival is in an operating room and that the goal is to have the patient in surgery within one hour of injury. It is particularly relevant for internal bleeding cases such as gunshot or stab wounds, and it underpins the scoop-and-run transport strategy.
EMS became an officially recognized subspecialty by the American Board of Emergency Medicine in 2010, with the first certification examinations held in 2013. Many states now recommend EMS board certification for newly hired medical directors of EMS agencies.