Jaegers

In one of the intervirew the director mentioned that some scenes will show what happends when one of the Jaegers is contolled just by one mind..instead of the usual two. I t was not clear if he meant one of the main stars were killed leaving one controlling pilot(I assume not) but another robot(not containing key actors) that show the effect of losing 1/2 of the operating team. In any case it does raise the question of why two minds are needed to control one robot(a rather large one). And more importantly a weak point that the Kaiju could exploit to take out a enemy. Why would the Director reveal this plot point so far in advance of the movie's release?