If Eliezer Yudowsky came to your house and handed you a gun and said that he would need your help with killing some people, that there was a very good reason for doing so and he would explain on the way there, would you get in the van?

Bearing in mind, of course, that he's convinced people to let an unFriendly AI out of the box, so once he gets you alone he'll probably be able to convince you of just about anything.