Self-sacrifice

His death was a sublime self-sacrifice.

Talk to your pieces, ask them where they would like to go, whether they would like to leave the board or even self-sacrifice for the greater good.

Honestly, I think if Mary had admitted she knew damn well what she was doing, and was understandably guilty about that, I'd have more sympathy for her. Altruism and self-sacrifice are fine to talk about, but actually being willing to give up your life for someone else—which is probably what refusing to rat people out to the bad guys would have come to, for her—is a pretty tall order. Not everyone is that brave, and being forced into a position where she had to choose between her own life and the lives of the people around her was a miserable and unfair position the villains are responsible for putting her in. She didn't do it unprompted.

Caring for a loved one with a chronic illness inevitably involves self-sacrifice.

Whatever he was suffering, it was she who had caused it; he had vacated his house on account of her. She was not worth such self-sacrifice; she should not have accepted it of him.

Some of those boys came straight from the cornfields with only a summer’s wages in their pockets, hung on through the four years, shabby and underfed, and completed the course by really heroic self-sacrifice.

Turians have a strong inclination towards public service and self-sacrifice, so they tend to be poor entrepreneurs.

[…] he turned his resourceful mind away from the serene life of a don on grass lawns in Cambridge to one of self-sacrifice and pure devotion in the thorny bushes of Africa.

His brave self-sacrifice won him a posthumous medal, but I think he'd have preferred to receive it in person.

[Scott’s Last Expedition] had been one of my own favourite books. It seemed curiously dated now, this heroism with only the ice for enemy, self-sacrifice that involved no deaths beyond one’s own.