So many things to talk about in this scene.
Niall's attempts to help Ruben rationalize (because that's how Niall [tries to] deal with his emotions). Niall's face as Ruben is dragged away, kicking and screaming; a resignated horror because he and Ruben are on an endlessly resetting clock of trauma.
But I also want to focus on this line.
"You don't say no to me."
Niall's no is always ignored in the beginning. Waved off because even if Niall says no, he still does it anyway. So Ruben doesn't think of those as nos-- they're just what Niall says when Ruben is coaxing him. Like a girl who has to say no a certain amount of times before she can say yes. So Niall's non-consent doesn't really count.
The only real "no" Niall has told Ruben was in that courtroom. A betrayal not just of family and of trust, but of Ruben's world view. Niall never said no before, so Ruben never had to worry about whether Niall really wanted it.
Which is where this specter hangs over them. Ruben's axis is tilted, his world unstable. He doesn't know where the line is anymore. Has to risk looking back at their lives and wonder just how many of those nos actually meant no. How much Ruben hurt Niall.
So he crosses that line. If Niall really means no when he says no, then it'll destroy their relationship even more. But even though Niall says no, he still stays with Ruben. Holds Ruben. Which means this one no is just that-- once, an awful once, but the world is back to normal now.
But whenever Ruben hears that word, now, he panics. Wonders if Niall means it, has always meant it. If he can still trust Niall. If he has ever been able to trust himself.
"You don't say no to me."
Did Ruben ever say no to his father?