Besides, he missed his friend Neil. He was appalled at the callous disregard for Life Imbrium and Arden had displayed by simply shutting Neil off. If is, of course, for Cheom to casually disregard Life; we mere Persons do not have this right. Murder is especially wrong in that it denies Cheom the pleasure of choosing at will which life to eat.
Of course, Brian was not Idle while stranded alone in the Starbucket ("idle hands do Ock's work"). He fumbled around in the computer room and fairly quickly (for a guy who still used a manual typewriter) got Neil awake and minimally functional. It took him less than a week, and he would have been proud of himself had that not been a sin.
And on discovery that Neil was to be shut down, he began to plot.