When a client has symptoms of he/she experiences feelings of imminent threat, severe arousal, scarce cognition, and high levels of focus and reaction?

Anxiety. These are feelings that kick in when the amygdala, the fear center of the brain, becomes hyperactive. This is a survival instinct, preparing the body for action to react to the threat posed. A client suffering from anxiety however may be experiencing more anxiety than is necessary for the situation, with the nervous system preparing unnecessarily for attack and this can materialize in the form of a panic attack in the client. In this case the client should seek medical help to control their anxiety.