Board Thread:Warhammer 40k General Discussion/@comment-91.224.27.226-20131031140001/@comment-24332685-20140102012138

Mind wiping is plausible since it would ensure none of the remaining marines that are incorporated into the ultramarines or other legions has any memory of the incident. I am not saying it is not possible since of all the legions they had control of the largest domain in the imperium. But unlike many of the chapters of the 41st millinium who tend to recruit from a number of worlds the legions recruit from one or a particular grouping of worlds.