long shot vs on thin ice

long shot

noun
  • A master shot, the primary wide shot of a scene into which the closeups will be edited later. 

  • A shot fired at a distant target. 

  • Something unlikely; something that has little chance of happening or working. 

on thin ice

prep
  • In a dangerous, hazardous, or delicate situation; at risk. 

adv
  • dangerously, hazardously, delicately 

How often have the words long shot and on thin ice occurred in a corpus of books? (source: Google Ngram Viewer )