After doing so well recently, this is where Tasuku trips... he certainly choked at the end of this chapter. The fact that he didn't understand the screenplay counts as critical feedback by itself: "it's difficult to understand, for a boy of his age." Shia is understandably embarrassed and probably disappointed (either with him or at herself, or both).
If that screenplay were like the contents of Shia's heart, then her heart is definitely still a mystery to Tasuku. This love is not easy. Keep marching on, soldier.