While hiking on a beautiful summer day, you come across a man who looks very pale and weak and is breathing rapidly. His skin is extremely warm to the touch, he seems confused and irritable, and his speech is not clear. His water bottle is empty and he has no food. What do you do?
Give him mouth to mouth, he's not getting enough oxygen.
He's probably been bitten by a brown recluse spider. Walk him back to the trailhead and instruct him to drive to the nearest fire station.
Give him a sandwich. He clearly has a low blood glucose. Make sure he starts to gain strength within the next 15 minutes. If not, take him to the nearest hospital, fire station, or even a police station for immediate help.
Call 911 if you can, if not, have a member of your party go a place with cell reception and call 911. This is a life-threatening situation. Get that man some water ASAP, put him in the shade, fan him and do anything you can to cool him down.