I was enlisted in the Navy back in the 80's.
I knew from then, if an officer was not promoted on a regular basis they were, I think, asked to resign. This guy is not only slapping officers in the face, he is actually reducing the number of officers in the military.
Some places don't fire unless the issue is repeated, client-facing, or willfully dangerous (like assaulting co-workers). The theory is: This is the first time this has happened - we learned from it, the engineer specifically probably learned from it. This won't happen again.