Final answer:
Governmentally run EMS services are protected from being sued by the legal doctrine called sovereign immunity, which is based on the principle that the state cannot be sued without its consent.
Step-by-step explanation:
The type of immunity that protects governmentally run EMS services from being sued by persons they treat is called sovereign immunity. This legal doctrine makes states immune from lawsuits with out-of-state citizens and foreigners not living within the state borders, and lays the foundation for the government's protection from certain types of legal action.
Sovereign immunity stems from the principle that the state or sovereign cannot commit a legal wrong and is immune from civil suit or criminal prosecution, hence EMS services run by the government are also afforded this protection.