People v. Unger
Illinois Supreme Court
362 N.E.2d 319 (1977)
Francis Unger (defendant), held at a minimum-security "honor farm," was sexually assaulted by three fellow inmates, received ongoing threats of further violence, and then got an anonymous death threat after word spread that he had reported the assault; without reporting any of this to prison staff, Unger walked off the farm and was caught two days later, testifying he fled to save his life and planned to return once he found help. The trial judge instructed the jury that Unger's reasons for leaving could not be considered a defense, and he was convicted of escape; the appellate court reversed and ordered a new trial.
Whether conduct that would otherwise be a crime is justifiable by necessity when the defendant was blameless in creating the situation and reasonably believed the conduct was necessary to avoid a greater public or private injury.