While I am not a fan of 15 minute web videos this one is a pretty good watch. You get a Gunsite instructor (Gunsite trains scores of people each year on everything from excellent hunting skills to civilian defense to elite US Military forces) and he gives you the lowdown on cover, cover vs concealment (hint: cover is always better) and how to use it – remember that you need to travel to cover in most defensive situations.
Many instructors say that if you're ever caught in a SHTF situation in a public place your priorities should be : get to cover (or concealment if that's all theirs is) assess the situation for threats, then draw. It makes sense, doesn't it? Why present yourself as a target for the bad guys? What if you decide that you don't have a shot?
Remember that your first responsibility is to protect yourself and your loved ones-if you don't need to identify yourself as an armed citizen why broadcast it?