Often after events like the horrific mass murder in Colorado, I am asked for tips on how security could be improved or how individuals should prepare for and respond to an emergency such as this.
Unfortunately, there is not a lot to be done to protect oneself from random acts of violence. Venues such as malls and cinemas that draw large crowds of people could screen bags and post security at all entrances and emergency exits, but that would require increasing the security presence tenfold or more. Given the expense of the added security and the rarity of events like the one that happened last week, it is unlikely that this will happen without some sort of governmental mandate.
Personally, there is also not much you can do to protect yourself in this sort of situation aside from being aware of your exits and selecting seats that would allow you to escape quickly in the event of a fire or other emergency. For example, many people prefer seats that are in the middle of the theater. While that may be best for viewing the screen, you could have a dozen or more people between you and the aisle and you are at the furthest point in the room from any exit. You would be at an extreme disadvantage if you needed to get out quickly.
We do recommend that people carry a handkerchief or small towel and a bottle of water with them if they are going to be in a crowd situation. In the event of a fire or other event involving noxious gasses, you can wet the handkerchief and hold it over your nose and mouth. This will filter out some of the fumes and give you a better chance of escape.
Overall, this type of tragedy is still very rare and there is no point in avoiding restaurants or theaters in the United States. We should all simply be more aware of our surroundings and think ahead about what we would do in the event of an emergency.