I have something pretty similar to that too, I just call it “Chained Thoughts” where one thought freely flows into another based on some relation between the two ideas, for instance I could start by thinking of a rainbow, then mabye the color orange, then mabye the fruit orange, then mabye orange sherbert ice cream, then mabye Braums, and so on. It just happens that you started with a bullet in somebodys throat (and what would happen therafter).
Thats something that i do all the time. I cant really control it sometimes and my mind seems to wonder at the times im really trying to focus on being lucid or astral projecting, then i end up just falling asleep…it really is frustrating sometimes 
i always think of being somewhere i have been before, but than i realize i have never been there before
Dude I find it effing hillarious when that happens. I can never remember what it is I was thinking RIGHT after I finish my thought… But I just think… What in the hell was I just thinking about? All I remember is that my thoughts were definitely trippin’ balls.