set out vs walk off

set out

verb
  • To go out, leave. 

  • To explain something, or give exact details, usually in writing. 

  • To position, to put in a position 

  • To start an activity with the intention of finishing it. 

walk off

verb
  • To flee or abandon. 

  • To measure a distance by walking, as by counting paces or extending a measuring tape or rope. 

  • To recover from (a minor injury) or digest (a large meal) by walking around. 

How often have the words set out and walk off occurred in a corpus of books? (source: Google Ngram Viewer )