As a white, straight woman, I say this to you.
You save them. Because if you don’t save them, even though God knows they don’t deserve it, you become the story and they use your righteous anger to justify their bad behavior.
You save them — because we do not yet live in a post race or post bigotry world, and your lack of action will be used to justify their actions the next time they run over someone and keep on driving. You save them because the outrage against you or someone like you will be so much greater than when one of them does it to the rest of us. An action like that on the part of a black person, an gay person, a transperson — heck under certain circumstances even a straight white woman will be seen as far more heinous and will be blamed on all of us while a similar action by an old white bigot will be blamed on his age or his upbringing and confined to himself alone.
Don’t think of it as morality — think of it as practicality.