I have dark thoughts, this isn't news to anyone.
Some are very very dark. Some would easily destroy in a moment everything around me if I let them take hold. They're ones I don't like to even admit to, that scare me because I realise what they would do. They exist in a firmly closed box that I bury so deep I usually forget the box itself even exists let alone its contents.
Once in a while the box creeps open. A comment or a thought process in my own head takes a lateral step and makes a connection to some other line of thought.
I've learnt to recognise that incipient other thought; the opening of the box before the full idea comes out and announces itself.
If I'm lucky I can stop it there. A half second while the thought process completes in which every other part of my brain is filled with urgency and alarm. Panic. Fear. The need to do anything in the very brief window of time I can still save it. Stop. I cry out loud or in my head. Stop stop stop.
If I'm lucky it aborts. Pandora's box shuts again before anything gets out and after a breath I go back to who I was; broken but functional.
If I'm not lucky... White hot rage at everything I've ever encountered or could encounter; the utter idiocy of it all, the insignificance. It can all burn. It should all burn. Every second I abide the world longer without destroying all I see is a failure of myself and my crystal clear understanding. I pray I'm alone when the thought latches on. I won't be less destructive, but my own life is easier to salvage when the dust settles.
One day maybe I can deal with these parts of me. For now there are other bits which are less dangerous to tackle. I continue to cry stop, and wonder what good it does.