Cosmoline-
Condition Yellow means you are going about your business, but always have a backup plan, escape route, or cover available to you. You are going one place, but have in your mind a plan to move somewhere else if your primary plan comes unglued. If you have no cover available, you're either in Condition White, or consciously taking that risk and knowing the nature of that risk.
If there is a commotion, you keep moving- going about your business, executing Plan A. While you are moving, you assess what the commotion is, what it means, and whether or not it is a threat to you.
If you determine it is a threat, you go to Condition Orange. Instead of going about your business, you execute the backup plan you made while in Condition Yellow. You move to cover, and while moving there make the plan for how you will respond to the threat. Moving to cover is not a response to a threat. It is what you do so that you can choose a response from a safer place.
Once you have gone to Condition Orange, Plan A is discarded. Plan B is the new primary objective, and you must start making a new backup plan immediately. You move to cover, and think of what you are going to do to break contact, or confront the threat, if necessary.
Keeping moving is not simply a matter of keeping your body going on a predetermined path from point A to point B. You keep your mind moving, as well- always looking for the next escape route and the next viable cover, and always ready to discard a plan that has outlived its usefulness.