I keep hearing how Gotti had respect for Roy as a killer. That said, I don't think that would have deterred Gotti. He was willing to kill a boss in the face of potential repercussions from anyone inside the family and outside as well (I've heard conflicting reports if he got approval or not - i can't imagine the commission okayed Castellano's death since they all seemed to be making money together, although that is my own speculation). He waited out Dellacroce before killing Big Paul out of respect, but all of Mr. Neil's schooling about the rules, etc., did not alter his course of action.

Just my two cents

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