Finally a solution

Might be the lack of oxygen. (If you poke holes it stops being soundproof)

Also why is he playing tic tak toe in school?

Let’s cut the kid some slack. The existence of this product strongly implies any kid you’d find under that done has probably spent the majority of their life inside that dome with no direct human contact. The fact he isn’t holding his knees and rocking- or can even write- are pretty impressive.