You're in public, minding your business, on your way to work - and gunshots ring out.
This rare, but terrifying scenario is something that all of us should consider with the prevalence of mass shootings in modern times.
There have been five in the U.S. just this year alone, not to mention the staggering number of gun deaths in America.
So here are immediate actions you can take to ensure your survival, which I learned during my time as a U.S. Marine.
Don't freak out. Don't scream. Stay calm.