(Page 193) When considering Walter Macmillan's freedom, what does Stevenson mean when he says that "this whole nightmare...would likely never be completely over for him"?

After six years on death row, Walter McMillian is exonerated and freed. Stevenson recounts how close he and Walter remained after the case closed. Walter's life is not necessarily happy after his release: the trauma of living on death row stays with Walter, who succumbs to dementia and physical degradation.