I remember Roy murdered a made guy from another family before he was even made and Nino just pretty much told him to "make it look like something else" and they made it look like a robbery gone bad.
That gave Nino Gaggi added power over Demeo. Demeo had to be at least smart enough to know that Nino could get him whacked if he divulged Roy's past to a Boss.
What I find interesting in Murder Machine is the part of how Nino genuinely wanted to convince Roy that being an unmade associate was much better for him. Unlike a button, an associate has a much higher tolerance for mistakes and can move more freely, etc. Roy wanted his button so bad, but neither Paul or Nino were okay with that.
Maybe in a way things would have turned out a little different had Roy not been made?
