[100 Words is a story in 100 words or less, based off the word in the title.]
It is insidious. The controlling urge that you will soon die.
A primeval panic. It create the fight of flight response, it causes adrenaline, it makes you pumped up. Ready for what happens next.
You become hypervigilant. You notice everything. Time slows. You notice motions, movements, things that would be dangerous to you. You see and hear everything, every noise is a potential danger, every smell is something that will hurt you.
You have to flee. You have to fight.
But you cannot flee.
You cannot fight.
So you sit.
Paralysed with fear.
Unable to do anything about it.