This diagram is meant to indicate that the FC gets partitioned off in the personality. It is hidden away from the environment and thus the sensitive parts of it don’t have to deal with any future ‘shocks’ that may come.
This permits the person to desensitise. When the FC hides away the person is desensitising to their environment especially to those circumstances that the person found very unpleasant. It is these sensitive emotions and aspects of the FC that hide away and thus the person becomes less ‘sensitive’.
Desensitisation makes what is emotionally abnormal become emotionally normal. For instance a soldier in a combat zone may have considerable painful emotions when he kills his first person. After he has killed ten people then his emotions about killing are far less dramatic and painful. This is because his FC has been partitioned off and he has desensitised to killing which allows his Child ego state to be much less sensitive about it. Thus what was once emotionally abnormal for him becomes emotionally normal.
Desensitisation is usually portrayed as a negative kind of process as we hear phrases like “children desensitising to violence” and so forth. However it is a normal psychological process and indeed has a positive purpose. If the soldier did not desensitise then in a short space of time he would emotionally collapse and simply could not function. He would psychologically breakdown and be rendered incompetent and inept. Such desensitising allows him to function and survive the traumatic episodes.
Trauma debriefing is designed to halt the partitioning off of the FC and the person once again gets resensitized. The sensitive aspects of the personality are coaxed out by the therapist and the person then can give up the partitioning off process and can again experience the world as a safe and OK place.
The problems occur when the degree of desensitisation is too intense or too protracted. If the partitioning off is strong and goes on for too long then the individual will begin to psychologically breakdown. They get a thing called PTSD which means the following happens to them
Persistent reexperience of trauma (e.g. flashbacks, nightmares)
Persistent avoidance of stimuli associated with the trauma (e.g. inability to talk about things even related to the experience, avoidance of things and discussions that trigger flashbacks and reexperiencing symptoms fear of losing control)
Persistent symptoms of increased arousal (e.g. difficulty falling or staying asleep, anger and hypervigilance)
Significant impairment in social, occupational, or other important areas of functioning (e.g. problems with work and relationships.)
If the FC is partitioned off for too long then the personality begins to collapse in the ways just described. Desensitising is a positive process in the shorter term but without the Free Child getting its basic emotional needs met in the longer term then humans will begin to fall apart. Trauma debriefing allows the person to once again emotionally resensitize and thus the symptoms of PTSD diminish.