escape route vs let-out

escape route

noun
  • A way out of a difficult or unpleasant situation. 

  • A path used by someone to escape from a dangerous place. 

let-out

noun
  • An opportunity to avoid or escape from a difficult or unpleasant situation. 

  • The act or an instance of releasing or letting out something. 

How often have the words escape route and let-out occurred in a corpus of books? (source: Google Ngram Viewer )