を救うために

in order to save

→ を
phrase Rare #42,218
in order to save Used after the person or thing being saved. 救う means “to save” or “to rescue,” and ために expresses purpose.
JA: 彼は町を救うために戦った。
EN: He fought in order to save the town.

彼は彼女を救うためにをかけた

He risked his life to save her.

ボロミア我々を救うために亡くなりました

Boromir died to save us.

— ロード・オブ・ザ・リング/王の帰還 (2003)