Meh, the Kyuubi was approving of Naruto with impressed laughter when he "admitted" that he would die. Moreover, he ended that sentence with "Eh?". He liked the extortion more than he was afraid of the threat. http://www.onemanga.com/Naruto/95/16/

Also, Naruto's seal has become weaker. So even if the Kyuubi was stuck in Naruto if Naruto died before, it might not be anymore. After all, the Mega-Bijuu would have escaped from the Sage of the Six Paths if he hadn't split it up.