Hi. The reason behind the intense rage could be the emotional trauma. There person has not dealt with the trauma effectively and the suppressed emotions tend to come up in the form of anger, frustration or rage

The intense rage or Snget  may be due to the bad experience  and also to the extent that they cldn't do anything  at that time. They feel bad about themselves. If they could understand and accede situation and people at that point of incident,  may be it might help them to come out of that regeneration. Please visit a psychologist  to  make them understand this truth.