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7. The law of Techum Shabbos by one who helped save another Jew:
All that have gone to help save Jewish souls from gentiles or from [drowning in] a river or from [dying] in a collapsed building, then they have 2000 cubits [.60 mile] radius from every direction from the area that they came to save the person.
If one fears danger in remaining in the area: However, if the gentiles are powerful and the saviors fear remaining in the area where they accomplished saving the Jew, then they may return on Shabbos to their areas and carry their weapons with them.
A midwife: One who left the Techum due to Pikuach Nefesh, such as a midwife which left to help a woman give birth and cases of the like, he has 2000 cubits radius from every direction from the destination. This [radius distance of walking] is allowed in order not to cause one to stumble in the future, as if one were limited to the 4 cubits of his destination, he may refrain from going [to help someone on] the next opportunity. In a case that one arrived to a city, then he has the same Techum as do the inhabitants of the city and [may hence walk up to] 2000 cubits from outside the city parameters.
One who traveled outside of Techum Shabbos to help save another Jew may walk within 2000 cubits from his destination. If he arrived in a city, he has the same Techum as do the city inhabitants.
May a doctor/EMT which drove a patient to the hospital return home on Shabbos?
If one estimates that he will be needed to assist more urgent cases in his hometown then he may ask a gentile to drive him home, and if need be even drive home himself.
If, however, he does not estimate this to be the case, then he may nevertheless ask a gentile to drive him back home, however he may not drive back home himself in his own car. If, however, there is no gentile available and there is worry that prohibiting the doctor from driving back will cause him to delay or neglect helping in emergency another time, then there is room to be lenient.
 Admur 407:3
 Admur 407:1
 Piskeiy Teshuvos 329:5
 As if we were to not allow him to be lenient by Rabbinical matters there is suspicion that he may delay going next time. This is similar to the allowance for the soldiers to carry back their weapons.
 So rules Igros Moshe 4:80