Dan Woolley, an American filmmaker trapped in the Haiti earthquake, used his iPhone for survival until he was rescued 65 hours later.
Woolley was caught under a pile of rubble when the earthquake hit, which injured his legs and his head. A first-aid app gave him the instructions on the best way to create a tourniquet for his leg and bandage for his head and warned him against failing asleep after head trauma, so the phone was also used as an alarm which is set to go off every 20 minutes. More here.
iPhone to the rescue!