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.
(..) It only takes aspirins to kill yourself. Hey. Put that money back, young lady. First you gotta take the safety off. Put it back. Go ahead. Put me out of my misery. It was just a joke. If I hear any more shit (..)1996 Foxfire