Yeah, because if you turn you could infect someone else.

I think you should devote the rest of your conscious life to helping others as much as possible, yet put yourself in a position so that you can be easily killed once you turn.

I'd do it if it meant saving someone.

I would think so. Or, at least, seclude yourself from others, make sure you can't hurt anyone when you turn. Exceptions would be if you had to accomplish something incredibly important (such as protecting someone), other than that I feel it is your responsibility to do all you can to prevent you from causing harm to survivors.