http://www.japantimes.co.jp/cgi-bin/getarticle.pl5?fd20030511tc.htm
"This wanted criminal wouldn't say where his buddy was located, so I put a single bullet in my revolver, shoved it against his head and pulled the trigger. It was a kind of Russian roulette," he says.
Hence the expression 'You're a fucking lunatic and I want absolutely nothing to do with you'