An American documentary filmmaker Dan Woolley was trapped in the collapsed walls of the Hotel Montana in Port-au-Prince, Haiti when the earthquake struck. He had badly broken one of his legs.
He used his camera’s flash to light the space so he could figure out his surroundings, which allowed him to spot an elevator shaft. He crawled to that to await rescue but here is where it gets juicy!
He used Pocket First Aid and CPR, a $3.99 iPhone app from the American Heart Association to instruct him on how to dress the break in his leg along with the wounds on his head. Lastly the app let him know that if he fell asleep it could be fatal, so he set his alarm to stay awake which worked for the 65 hours before he was rescued by non other than a french team. Check out the video:

I would be money that he went into airplane mode to save juice. My iPhone wont last a day.