פירוש על עבודה זרה 54:2

R. Yohanan says that if the Jew will certainly die without the non-Jewish doctor’s medical attention, he should be allowed to heal him (or at least to try). While it is true that that the non-Jew might kill him immediately and thereby cause him the loss of the few hours/days/weeks he has left, we are not concerned with loss of such a short amount of time to live.