Peekaboo! Stray Kids

In the Korean comments

Listen for Changbin’s vocal reaction: one top comment reads, in translation, “Changbin’s scream.” Another comment turns the scene into a family-style joke, describing Changbin lying motionless on the floor while “Dad” keeps dancing and imagines the thought, “Leave Changbin to sort himself out; I’m going to keep dancing.”

What the words mean

세상에 (sesange, literally “in the world”) opens that family-style comment, but here it works as the casual exclamation “Oh my” or “Good grief,” setting up the exaggerated joke rather than referring to the world.