The climbers were roped together for 'safety'. = The climbers were roped together 'for safety's sake'.
There is 'safety in numbers'. [=you are safer in a group of people than you are when you are alone]
His hobbies act as a 'safety valve', relieving some of the pressure he feels from his job.
(..) Where's my child? She's not your child. She's hers. The little girl is what's left of her goodness. We hid her in safety... ...in the world outside this hell. Now the dream of this life must end... ...and so, too, must the dreamers within it. (..)2006 Silent Hill