This is coolbert:
As it was almost two thousand years ago as it is now.
The Orthodox Jew during a time of war relying on the pronouncements of the rabbi, teachings as how to fulfill your religious obligations during a time of war or emergency.
"You can leave radios on over Shabbat, says Tzohar chief rabbi"
"Rabbi David Stav says radios may stay on so that sirens can be heard • Stav urges Jews living in areas under rocket fire to avoid walking to synagogue, and says reserve soldiers can answer phone calls on Shabbat."
During the Bar Kochba rebellion against the forces of Imperial Rome, the Roman taking advantage of the Jewish Sabbath. Jews their sacred teachings for that single period of a day not allowing them to defend themselves.
Rabbi Akiva at the time declaring in response that: "during a time of war all laws maybe set aside except for apostasy and murder".
Do what is necessary during a time of war or emergency for your defense.
Answering a phone call [possibly an emergency message] is considered according to the Orthodox Jew as being the same as lighting a fire [forbidden Sabbath behavior]. Starting an automobile to drive to the synagogue during Sabbath also the same as lighting a fire [the ignition makes a spark].