 if they were on "remote control" by the same  entity (the Nexus), there would be no need for them to talk or  signal, the Nexus would simply relay any info directly through the  neurocyte, and they would also be steered in combat, based on their  "experince" feeding back to it. Also, we hear lt. Voss pleading to  be killed long after his stroggification has kicked in, suggesting  that he is a conscious witness to his new body trying to kill Kane  and that his higher brain functions are intact, just not in control.