...

Because some personal reasons i ll focus more on gangs issue :)

It is very important to understand who is typical member of gang in SHTF. As i already said before, worst kind of people is in charge in SHTF. Usually they take lead, so you have then old criminals as a new gang leaders, of course you already figured they not gonna pay too much attention on moral issue or fair play.
In most parts of the world we already now in peace time have gangs, all kinds. In SHTF those gangs becoming something like private armies.
People joined them, it is easier to take stuff from other people then to find it on more "normal" way. So you gonna have normal folks who lost faith, lost strength, and for them it is only way to join gangs.
My point is to prepare you that in SHTF your first neighbor (who is now for example car salesman) may be very bad gang member.
It was much easier to be gang member.


It is hard to tell what you are going to need in SHTF in your medical part of prepping.
Easiest thing to say is that you gonna need everything, but actually it depends from your level of medical knowledge i guess.
for example:
Full reanimation kit- O2 bottles, respirator (O2 powered) suction unit (O2 powered), laryngoscopes, tubes, airways, BVM s, tube holders, drugs (atropine, adrenaline, dopamine...)
Body protection like masks (booth surgical and respirators), gowns, gloves (sterile and non sterile), lot of rubbing alcohol, hand sanitizers,paper sheets, delivery kits.
Wound care kit-  all sterile gauzes, peans, tweezers, povidone, rivanole, staples, sutures, forceps, dressings, antibiotic creams...
Vitamins, tablets and vials for injections.
Antibiotics full range, booth tabs and vials (Pennicilin, Gentamicin, Lincocin...) then full range iv fluids kit with NS and Glucosae, including IV systems, needles, syringes,  IV catheters ...
Children antibiotics, suspensions, together with antipyretics like Voltaren supositories.
Snake kits (horse serum), allergy shots (Urbason, Synopen...), urinal catheters...
Drugs like Furosemide, Novalgetol, Aminophyllin, Reglan, Ranitidin,  (all vials), Albuterol (inhallant).

List is going more, but important is to choose what level you want to know, then find way to learn to use things on that level. You can not know everything. Maybe you gonna choose only to have powdered things for hydration instead of IV NS.

Whatever you choose to have, keep in mind that must be as more disposable as you can. For example paper instead of fabric, or sterile plastic tweezers instead of reusable.
And again from my experience most of the problems were coming in the form of vomiting and diarrhea, due to bad water, or unknown food.