This depends on whether I knew I wouldn't survive. It's very much in the moment if you see a child heading into traffic (likely I'd be waving my arms and shouting rather than diving in).

I can't predict what exactly I would do if put in a situation like this because my normal reaction to most situations is flight. However, I think knowing myself well enough, I would probably risk my life (sacrifice) to save someone else's. 

At the end of the day, it doesn't matter who they personally are or anything that they've done that is damaging to their character. I think trying is better than not trying at all, so yes, I would sacrifice myself for man, woman and/or child.

I think this would on my mood. If I felt unhappy with my life, I think I would sacrifice myself to save someone. If I felt happy, I would not. 

This also depends on the person. If I really love that person, I would sacrifice myself for them.