Sane (by the usual definition, though it's possible you are using an unusual definition of your own) people jeopardize themselves to harm other members of the species all the time.

In fact, societies tend to have organized groups of people who are expected to do this when the targets are enemies of the group, and who are honored for it; they also not infrequently honor people who independently do it against people theor society has decided are "the enemy".