duck out vs walk out

duck out

verb
  • To move or act so as to achieve avoidance, escape, or evasion. 

  • To depart quickly or exit abruptly by way of, especially in a manner which does not attract notice and before a meeting, event, etc. has concluded. 

  • To depart quickly or exit abruptly, especially in a manner which does not attract notice and before a meeting, event, etc. has concluded. 

walk out

verb
  • To continue or persist in carrying (something) out or following through (with something); to persevere. 

  • To step away with when carrying the weight in order not to hit the rack it was lifted off from during execution of the exercise. 

  • To leave suddenly, especially as a form of protest. 

  • To stage a walkout or strike. 

  • To accompany (someone) as they leave a house or other building. 

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