Having never read Archie, no, I'm definitely not letting that influence my judgement. Shadow is (/was) used to be fairly calculated in his decision making. He wasn't just a "spur of the moment" kind of guy. Perhaps "level headed" wasn't the right phrase to use. But I definitely consider him to be the sort that thinks ahead. Always has a plan and knowd what he was going to do. That's why I don't see him lashing out against GUN as viable, and would sooner expect him to work with them. If he had and lingering grudges and ulterior motives, he wouldn't go ahead with GUN.