Could be he is trying to assert some control over his environment during a time when he's feeling loss of control. He may be re-living intense feelings of powerlessness, loss of control, from the past, and even the process of the memories surfacing is something the survivor has no control over. On some level he may be thinking "I'll get there on my own timetable and nobody else's." Likely its subconscious.
Sounds like you're coping with it as best as you're able.