It really depends on why the man is drowning. If he fell in, or someone pushed him in, throw him a rope. If he's just too lazy to try treading water, you have to wonder if it's worth it.

As to Abortion=Slavery: Souls only enter into the equation if one makes decisions based on religion, which it is a standing governmental policy to avoid. If you want to argue that a fetus is a person, I find that to be a rather difficult argument to make. A fetus cannot operate independently of its mother in any way. No evidence exists to support the idea that a fetus, or indeed a newborn, is capable of rational thought. While the line of personhood is extremely hard to draw, it seems self-evident that it does not include an organism which can do nothing but absorb nutrients from its host in order to grow.