As an example, I think I was around 16 years old and I was very much into sport cycling and Tour de France. When I lost consciousness a slide show of Tour de France competition accompanied by the TV commentators rush into my thoughts. All of it at very high speed and extremely overwhelming.

I think of it as an analogy of a memory dump of a process that is no longer running (consciousness), and everything gets just read and dump at high speed and without any sense nor capacity to make sense of it, only leaving a small impression in my short memory area which afterwards I was able to remember for longer time.