It's strange how a person can go most of their life thinking everything is rational, manageable and that most
things will have a positive outcome. Then one day you do something or experience something that shows you horrible things and causes you to experience fear beyond anything you ever thought possible. You see something that tears open reality to spill out the most awful visions and rips your consciousness away from your ego, your body, your self, your awareness. You begin to realize that everything you fear and those things you find most horrible and unthinkable exist in your own brain. These thoughts and things are contained behind doors that you were never meant to open... things forgotten with good reason, things you were never meant to see or see again.
I was watching "Deadliest catch" recently. In the cargo holds of crab ships, there are boards that divide the crab catch into parallel sections so that when the ship hits rough seas, the crabs won't pile onto and crush each other, causing them to release a toxin killing those around them. The doors in your mind are somewhat like this, protecting you from yourself in a sense. An engine as powerful and capable as the human brain cannot be left to contemplate unchecked. Once certain doors are opened, it is possible they can not be closed again. Things suppressed from childhood, sickening memories, thoughts so terrible that they corrode sanity, ideas that could become dangerous. The brain has the potential to be an unequaled machine of dark purpose.
There is a positive side effect. When you return from being completely stripped of your ego, being made to think you are going to die alone and horribly and being made to fear far beyond normal thresholds, you begin to appreciate life more than you ever have before. It's a perfect demonstration of high contrast. Death, no hope, intense fear, and then reaffirmation of life, hope, dreams, consciousness, return to control.
Some of that horrible fear stays with you though, and I have found it quite hard to ignore. Some things can't be unseen or forgotten... some doors can never be closed once opened. It is possible to see too much, and many of us carry this deadly cache of harmful thoughts and memories locked away in our own minds like old, forgotten ordnance, unstable and waiting to explode with the right stimulus or trigger.