This right here is why J doesn't tell anyone anything. Trying to explain his Music Sense has gone well exactly once in his life, and at this point he's pretty sure that was the exception that proved the rule. The situation right now isn't so much a return to form as it is taking form and making it a hell of a lot worse.

Sans' tune sounds like murder again, for a start. He'd be looking for an exit if there weren't half a dozen people - one of them Sans - between him and the door. There's panic in the Music, and fury, and a sharp undertone of fear - partly from Rarity, but mostly from Agent 3, because there's water everywhere-

This has gotten out of hand way too quickly. Someone has to rein it in, and that someone shouldn't have to be the kid surrounded by something that could mean her death.

J puts his hands on the table and, despite every instinct telling him to keep his eyes on the guy who wants to kill him, levels a steady gaze at Lapis. "Lapis. Put it away." His tone is oddly calm amidst the barely controlled violence in the kitchen. It has to be. He has to do this. He can freak out later.

That imparted, and trusting Lapis to do what he says, he looks back at Sans. "3's right. You wanna talk about this, we'll talk, but fightin' each other ain't gonna help anybody, an' I think you know that."