Especially considering Tony had NY's endorsement of him running the family behind Junior's back, adding insult to injury that Junior would be the one who took the heat from law enforcement since he was the boss on paper, and he did. Like I said, Tony barely respected Junior and played him like a fiddle, so having Junior's "number one soldier" Mikey whacked was an easy decision that came with no consequence, other than Chrissy being haunted by him in his morphine hallucinations.