The machine was doing a good job in balancing Rufus's two sides. It needed him to have that savage determination, whilst thinking things through. Rufus was convinced that he had to try and achieve the brain dump before exacting any revenge he felt must be administered.
The machine inculcated in Rufus the belief that since Marcus had been kept refrigerated, then there would have been no serious decay in the brain tissue. Thus he believed that his first objective wasn't pointless.
Exacting subsequent revenge was of course pointless, but the sheer satisfaction to be derived from it was certainly not!