A man was walking downstairs in a building when he suddenly realised that his wife had just died. How?
The man had visited his wife in hospital. She was on a life-support machine. As he was walking down the stairs all the lights went out. There had been a power cut and the emergency back-up systems had failed. He knew that she had died.
Alternative: The man's wife was suffering from depression. She was also suicidal. When he was getting down the stairs,she had jumped out and he saw her falling