Some of the parts of the mind controlled vivisectees got out of their
   vats.  Their brains were being used for calculating who boss's next
   competitor was most likely to be, and their bodies were being used as
   part of his immortality research, but something about their nature,
   something about their community, somehow survived.
   They had been through so much of this torture together, and together
   had learned how, even to meet the continuous demands of the
   computerised research, it was necessary to hide part of your mind from
   it.  It was these parts that communicated in shared symbols and
   references, and these parts that showed the computer why it was good
   for boss, for them to get up and leave.