Yer, our subconcious does that too us at times. Damn, that is a pretty good dream. Not only did you start of and save yourself, but you kept going until you found the resolution that you wanted. Now another spin on that thought of yours, being "saving myself" to "dying" with everyone else, could just be that you have found some resolution to now stick things out, and work on the actual issues at hand, as you didn't know exactly what was up until just recently, being your PTSD diagnosis?

Maybe you where running away not to save yourself, but in fear off facing what is to come? Maybe you sorted yourself out in one dream to know you need to face your trauma, and not run from it? The possibilities are endless...