You don't believe that Hax would have attempted to kill Bert and Roland to quiet them? To make sure he wasn't found out? In a gunslinger's mind, I imagine, a traitor didn't deserve a chance to say his side of the story.
I guess I didn't see it this way. I don't believe Steven was being up front with Roland. He isn't a gunslinger so I don't think Steven would let him in on their plans.