Personally , I think the whole ' Reyes was jelly ' lore is too weak . When you see what a huge change in character that Jack Morrison underwent when he came back as Soldier 76 . Something much bigger must have happened for the brighteyed , hopeful , and smiling Jack Morrison to go from a public hero to a growling masked vigilante who steals technology to track and defeat Los Muertos gang members from the shadows . 76 is a man who constantly sees himself as a soldier at war . He responds to seeing his closest friends and allies killed with the voice line Tactical necessity . He hesitated in choosing to pursue fleeing Los Muertos members or saving a young girl from a grenade . Whatever happened between Reyes and Morrison must ' ve been huge . Reyes was left wanting revenge and saw Morrison as leaving him for dead . Morrison became forever disillusioned and trapped in this manic state where he sees himself fighting a neverending war . I hope the reason given in firestrike is more than Reyes was jelly .