open fire vs pick off

open fire

verb
  • To begin firing (weapons) at something or someone. 

noun
  • An uncovered fire. 

pick off

verb
  • To shoot one by one. 

  • To dispose of tasks, obstacles, opponents etc. precisely, one by one. 

  • To intercept, such as a ball in flight. 

  • To throw out a runner by tagging them whilst they are not in contact with any of the three bases or home plate. 

  • To remove by picking. 

noun
  • An instance of throwing out a batter leading off base. 

How often have the words open fire and pick off occurred in a corpus of books? (source: Google Ngram Viewer )