Survive an accident with little injury, as in They were lucky to walk away from that collision. [Second half of 1900s]
Refuse to deal with or become involved, abandon, as in No parent finds it easy to walk away from a child in trouble. [Second half of 1900s]
Outdo, outrun, or defeat with little difficulty, as in The Packers are walking away from the other teams in their division. [Slang] Also see walk over.