Usually, if Shizuo here doesn't like someone it's for a really good reason. (Or just instincts. Same thing.) He's also rather bull-headed about some things (read: beastly 'simple')

So if anyone wants a group where he'll probably make it horribly (and hilariously to us) frustrating to cooperate, bam. I can guarantee that he'll offer to throw people ahead into the level, or just try and do it without permission, depending on the people around.