vacsell

I am new to baseball so don't think I am a complete idiot. I saw something at a game the other night I do not understand. The baserunner made contact with his own batted ball outside of the batters box on the way to first. He was clearly in foul territory when he made contact. The ball then went fair after the contact and the Umpires ruled him safe at first. Isn't the ball dead upon contact with a runner in foul territory?