What is someone threatening to do when the telephone rings at three?

Larry Smith is one of the rescuers on the Golden Gate Bridge. His job is to save people who attempt to jump into the sea. If the telephone rings at three in the morning, he knows it’s trouble. Someone is threatening to commit suicide. Larry will get his things ready, and in no time he’ll be out the door and heading to the spot.
     "If you aren’t too late," Larry says, "you climb out onto the cold steel and try to talk to the poor, and pull him anyhow back to safety. For many suicide attempts are made on the spur of the moment, and lives can be saved. But if you fall, if the person jumps into the bottomless pool, there’s no describing how helpless you feel. Often, would-be jumpers are driven to despair and see no hope out of their misery. The trick is to open channels of communication with them. Following are some tricks that have worked: If you’re going to jump, at least give me your mom’s phone number so I can call and tell her. Or ’That’s a nice watch. If you’re going to jump, can I have it?’ Sometimes, all it takes is the voice of the human being who cares."
   Larry estimates he has rescued about thirty people in his ten years of service.