Unaware - Non-responsive to the surrounding environment.  This state is inescapable most of the time.  If you are attacked while in an unaware state we consider this an ambush and your best chances of surviving is to weather the initial onslaught and then counter attack.

Aware - Conscious of your surroundings and the people in it.  You are simply aware that the world is a potentially unfriendly place and you are prepared to defend yourself if necessary. Awareness can help you avoid danger, give you more time to prepare a response, and can serve as a deterrent.

Alert - Something seems not quite right and has your attention.  Your senses have picked up a possible threat and your mind begins to set mental triggers (“If that person does X, I will do Y.”).  At this stage the fight or flight response is activated.

Alarm - Your mental triggers have been tripped and action must be taken.