The bottom line is that when memories leak out - the colonel is not able to function effectively. He freezes, and he has a very responsible job. In addition, he realizes that he is no longer Nielsen. But just a biorobot into which Nielsen’s brain was inserted with memories. Nielsen, as a person, in fact, has long been dead and buried. But centuries later, his brain serves the benefit of mankind, and all these memories, emotions - so sweet, but an obstacle to work.