Killing people to save lives. I'm sure that THEIR God approves! Conks is so smart!
The theology of it can serve as an interesting basis for discussion. But the general idea of killing one person in order to save another person's life when the second person is at risk of being attacked by the first person is a broadly accepted principle.
For instance: Someone has a conceal-carry permit and has their gun on them. They see a guy burst into the area and start shooting. One person goes down. The bad guy turns and points his weapon at a child. The guy with the conceal-carry permit has his weapon out at that time and shoots the bad guy. Drops him stone dead.
Not only would that be considered acceptable on a nearly if not totally universal level; the guy with the conceal-carry permit would be considered a hero.
What it all comes down to, as it usually does with the abortion issue, is the nature of the unborn. If your premise is that the unborn are just tissue and not living members of our species that have the right to life, then of course you think it's wrong to kill an abortionist in order to save the lives of the unborn. But if your premise is that the unborn are innocent human individuals with just as much a right to live as any other human individual then, regardless of the laws of the socieity of the time and place, killing an abortionist is perfectly acceptable from a moral standpoint. Every bit as acceptable as it would have been, say, to kill a NAZI about to pour Zyklon B crystals into the gas chamber in 1943 Germany. Such an action was, of course, legal according to the government in power in that place at that time. But just about everyone in our time and place would say that killing the NAZI to save the people about to be gassed would have been acceptable.
And, yes, regardless of how vehemently someone might protest, that is indeed a valid illustration of the principle. If you start off with the premise that the unborn are human individuals with just as much a right to live as any other human individual, the laws of this time and place with respect to abortion are very, very wrong. We have sanctioned the unfettered murder of millions of the most innocent individuals mostly, though we try to paint a less disgusting picture, to allow women the convenience of escaping the consequences of their own actions.