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.
(..) If I go without you, they'll take them away anyway. - What does that mean? - I filed a letter with our attorney... ...explaining how I'm fearful for my safety. How you have threatened to kill me. - Why did you do this? - I love you, Dom. Why did...? Why would you do this to me? (..)2010 Inception