I heard a psychiatrist discuss the case on Radio 4 (I think), he said in his experience people commit suicide when they feel they have failed to live up to the standards they set themselves.
Although to be honest there have been a number of strange suicides in the defence field over the last 10-15 years, eg - Marconi Underwater systems experienced a number of "odd" suicides
http://www.100megsfree4.com/farshores/secdeat2.htm
and
http://www.mysteries.pwp.blueyonder.co.uk/4,7.htm
I have a number of friends in the computer industry - several were offered contracts with GEC-Marconi underwater systems and they turned them down despite the hefty wads of cash on the table.