When your nervous system perceives danger and concludes that fighting back isn't the available option, it does the next most intelligent thing it knows: it prepares you to move. To get away. To put distance between yourself and whatever is threatening you.
The flight response is mobilisation directed away from the threat rather than toward it. Physiologically, it looks identical to fight activation — the same adrenaline surge, the same cardiovascular acceleration — but the direction is different. Instead of meeting the threat, you move past it, around it, away from it.
Most people who live primarily in flight response don't experience it as fear. They experience it as productivity, as ambition, as restlessness, as the inability to slow down or sit still. The anxiety is real — but it often lives beneath the surface of a very full, very busy, very high-functioning life.