"Oh..." Asriel was about to say why he wasn't going back into hiding, but the reason related to Flowey. Not in a negative way, actually, though his plant self might mistake it as an attack. He'll need to explain later once everyone has enough time to recover.

"Should I leave you alone then? If you need some privacy, I mean..." He can deal with Flowey's wrath, but he'd rather not Frisk get caught in the middle.