The Outer Limits - Season 2 Episode 15 Afterlife

Linden Stiles struggles to retain his humanity after heis convicted of a murder he didn't commit. When asked to make a frightful choice: accept execution or become the subject of a secret military experiment -- he chooses to live. As the experiment progresses, Stiles fights the dehumanizing influence of injected DNA from an alien lifeform. The attending doctor is troubled by a growing awareness of the inhumanity of the experiment itself, of the men in charge and of her own role. Using his super-human strength, Stiles escapes. Then, hunted by his former compatriots, he faces a decision even more difficult than the one that set him on such a tragic course.