Two people in a room alone. One looks around and realizes he's going to die.
Solution:
The two people are Siamese twins. One wakes up, notices that the other one is dead, and realizes he will die soon, too.
A man is driving his car. He turns on the radio, listens for five minutes, turns around, goes home, and shoots his wife.
Solution:
The radio program is one of those shows where they call up someone at random and ask them a question. The announcer states the name and town of the man's wife as the person he would call next. He does so, and a male voice answers. From this, he gathered his wife was having an affair.