So last night I got an interesting insight into this question. For the record I should add that I have not been through any experiences that would give me PTSD nor have I been through any intense military training.
We had some guests staying with us. One of our dogs was not socialized very well so we kept her in our bedroom during the evening and, when we went to be for the night, closed the door to a crack (so the cat can get in and out) with a small step stool in front of the door. At 5:30 am my three-year-old opened the door and the dog barked. I landed on my feet yelling in best kung-fu fashion. I was not moving to attack, someone with a gun could have dropped me where I stood (unless they shot in the direction of the dog first).
Two observations:
A) my primate brain was in control for a second or two, I was on autopilot ready for fight/flight with no warning prior to the sound to the bark.
B) I mentioned early in the thread that if things degrade and we feel threatened I have an idea on how to make the house not burglar proof but such that you would have to make noise to get inside. If I feel nervous (because TS is about to HTF), I have little doubt that I will be able to be up and have
the go to gun in hand before anyone gets the second leg in the window.