Just a question that came to my mind. Why Vader didn't allow Boba to shoot Chewie even though Chewie killed or injured 2 stormtroopers in the carbon freezing chamber? Did he feared that Han might have jumped in front of Chewie and taken the shot instead ? Or he did feel some pity toward Chewie? In terms of personality it doesn't makes sense for me since Vader was a ruthless guy that didn't shy away from finding excuses to kill more innocent and defenseless beings.