Comment by DrScientist

> What about saving 50 people, and then killing 49? Should they cancel each other, too?

Only if they were linked - you blew up a plane that was about to be flown into a building for example.

That's completely different from one day taking over a plane and landing it safely because the pilot was out of action, and the next day shooting down a plane for fun.

You can't save up to murder your wife by giving to the homeless.