One morning a man is leaving on a business  trip and finds he left some paperwork at his office. He run into his office to get it and the night guard stops him and says "sir, don't get on the plane. I had dream last night that the will crash and everyone die!" The man takes his words and cancel his trip. The plane crashes and everyone dies. The next morning the man gives the night guard 100000$ reward for saving his life and fire him.

what was the possible reason?

Answer will update soon