For those who have never faced mortal fear before, hysterical or temporary blindness, amaurosis fugax, may occur. This is sort of a visual "whiteout" that occurs because the mind has seen something so terrifying that it refuses to look at it any longer.
People may also experience a denial response, a feeling that this terrible thing cannot really be happening. This may cause a state of fugue, where the person appears to be in a zombie-like state. Sometimes the person feels disconnected from events, even from the things he or she is doing. The person may feel he or she is watching the entire scene from a distance.