Clear - bad place to be is that you are zero situational aware.
Blue - Your standard level, alert but not tense. Relaxed but taking information in.
Yellow - Something triggered your attention. You have already started thinking about how to escape or defend yourself. You grab your personal defense weapon.
Red - Training kicking in. Instinct kicks in.
Black - Freezing up. You do not want to be here cause you are dead.
Practice this and it will become part of you.
Timeless advice from this man : Best situation to win a fight is to avoid it.