@DS: I would like to note that Hasarian is no saint, despite what Jace thinks. He just has standards, albeit not very high ones, but there are some things he won't do.
@Xath: Remember that Bane is out in the KE to hunt down the rogue Guardsmen that killed his mates in a friendly fire incident. Also remember that he comes from an honour bound society. This sense of honour is burned in too the minds of every Prys Worlder from a young age.
While more ruthless and downright savage then his fellows in the Prys 152 Light Infantry, Bane still has a crude sense of honour and morals, that, while twisted, dominates his life.