I had very good eyes once. Though it's another thing to say what I saw. In my experience, it is entirely possible to watch something happen and not to see it at all.
The human brain cannot encompass total absence. Like infinity, it is simply not something that the organ runs to. The space someone leaves must be filled, so we dream forever of those who are no longer here. Our minds make them live again.
This vast life - the real, interior one in which we remain linked to the dead (because the dream inside us ignores trivialities like breath, or absence) - this vast life is not under our control. Everything we have seen and everyone we have known goes into us and constitutes us, whether we like it or not. We are linked together in a pattern we cannot see and whose effects we cannot know.
Betrayal clearly has its own reward: the small deep human satisfaction of having one up on someone else. It is the psychology of the mistress, and this regime used it as fuel.