594. Life-Saving on Shabbos
Shabbos 2:15
If a woman dies in childbirth on Shabbos, a knife should be brought, even if it must be carried through the public domain, in order to remove the fetus because it’s possible that the child will still survive. This is because Shabbos is violated even when there is only a chance of saving a life. We do so here even though there is no presumption that the child will live.
Shabbos 2:16
Anything necessary to save a life should be done on Shabbos, with no reason to consult an authority. The more zealous one is in this area, the better. Therefore, if someone sees that a child has fallen into the ocean, he may spread a net and pull him out even though he also catches fish. If he spreads a net to save the child but only catches fish, he is completely exempt. If he intended to catch fish and ended up both catching fish and saving a child, he is not liable; since he rescued a child with the fish, he is exempt even though he was unaware of the child.