🚀 go-pugleaf

Another possibility as far as the door slam/gunshot in a dream is
concerned, besides the dream being manufactured instantaneously, is
this: a gunshot is a surprising or startling thing. If there was a
door slam, it would also be unexpected, and this would be consistent.
At least in my case, I never wake up instantly, so the dream has a
chance to "wrap up" before I really gain consciousness (though I 
realize that most people sleep more lightly than me). It may be that
although you thought that you anticipated the gunshot, it may have
actually been a surprise in the dream, albeit one that fit the scenario
and was thus incorporated as a surprise. Given the circumstances, it's
quite easy to believe that you remembered the dream slightly wrong,
and the gunshot was a surprise. If the "bang" had not fit the scenario,
you probably would have just woken up and ignored the dream, so there
is a bit of coincidence involved here.

I know what you mean, though. Many times I have turned off my alarm
clock, turned on the radio, stumbled back to bed and drifted to sleep.
News reports in particular make for very odd dreams. Unfortunately, this
gives me a bizarre view of current events, because I'm never sure what
I really heard on the news and what my mind made up.

                                     Jean-Joseph Cote