I get this after a few minutes of relaxing in bed. I believe what is happening is that his mind is playing through recent memories and altering them, as if he could've or should've done something else. My first "half dreams" tend to stem from memories that get altered, by their own accord, and play out. I'm usually in them but it's more of a third person thing. As they get more deep and vivid, my mind usually falls asleep and my mantras are forgotten. Wish somebody could help me find a decent anchor or something!