This sounds very much like the sort of little flashes I would get when my anxiety was strongest, usually when I was just waking up. My mind would dash me through a number of scenarios that felt like some sort of punishment. I get what you mean about running through those even when you don't feel anxious, I often watch things involving people standing on top of high buildings and when the camera gives you a long, vertiginous shot I feel a bit odd and now and then get this little movie running in my head of falling from that kind of height.
I would say that this is just our deep seated fears and depression working away and coupled with the anxiety we're going through it heightens that, turning it into something akin to mental self harm in a way. It's just a way for the anxiety to reach you and as you'll find out over the coming weeks, it will try to find lots of little things to use against you, this one is just one of the less subtle ones.
Better days Yvonne
Shaun