When I was a MS I was involved in the prison ministry and I worked with many prisoners, including death row inmates in the state's most secure supermax facility. I had direct contact with them, not separated by glass or bars. One particular death row inmate wanted to be executed and get it over with. However as his case was going through the appeals process there was the possibility that his sentence would be commuted to Life Without Parole. He did not want to spend the rest of his life in prison so he killed himself. I don't blame him! And I'm sure there have been other cases like this.
Also, Luo bou to posted: "I don't see why suicide can't be a rational decision" I thought of the example of the Twin Towers on 9/11. Some who were trapped inside realized they were going to perish in the flames, and therefore decided to jump to their death.