As I understand it…That’s exactly how mobile phones work when you dial emergency number. if your operator has no signal, it automatically selects the strongest cell signal and attempts it through that. And you don’t even have to know the country equivalent number, dialing 911 will automatically route to the local emergency center. There’s a list of numbers that are recognized as emergency numbers by the phone/sim, but the actual number is not even used when the call is initiated. In general as long as you have a phone with battery left, you should be able to make a call to emergency center.