You can change the constant scanning, requiring to sit near exits, or see exits, etc... you can change all these behaviours. Because the military put them within us, and then combat reinforced there validity that saved us, in essence, as we came home, the difference is now through the very same repetitive training we undertook in the first place to get drilled with these aspects, to undo them. I will say though, because they have been reinforced by combat, they are harder to change....
Will you ever completely remove them 100%? No... and the reason is because it will depend on your mood. If you get yourself to the point where you're going to the shops, feel good going in, good coming out, then you can absolutely change your behaviour with scanning and being alert. When habits will come back though is when you enter a shopping center or such, and your anxiety is already heightened... then your brain tells you that your combat training is required, even though its not... but anxiety dictates differently.
Change the anxiety and stress levels period, you also change the other negative behaviours of scanning and being hypervigilant.
How do you do that? Through exposure and practice, practice, practice, repetition, repetition, repetition in actual locations. Literally, focus on being completely blase within a shopping center, walk through, bump in people in crowds, etc... apologise, reinforce the difference of civilian environment to combat. Bumping into someone here is an accident, not a threat... even though you are intentionally doing it as part of self retraining... they don't know that. But it works...
Work at the core of the issues... lower overall anxiety, back it up with exposure, and lots of it. You suddenly find yourself within a crowded shopping center for hours, without coming out all worn out from constant scanning and alertness... you just relax and browse / shop.
Use logic... when someone is frustrating you, logic dictates, you may just as well be frustrating them, either walking too fast, or not fast enough. Crowded shops.... others are just as frustrated as you are, use that logic to keep calm, keep anxiety down, and look around whilst in lines, or say, excuse me, to get past someone... lots and lots of practice makes perfect mentally.