Haruki hears about Kazusa's moving from her mother, who she hadn't been on good terms with.  He feels betrayed and angrily confronts her.  But his words force open the door to Kazusa's heart, which she had desperately tried to keep closed so that the three of them could stay together.
I won't look at it when 
you're writing it, so...
Ich werde nicht hinsehen, 
wenn du schreibst, also ...
No espiaré, así que...
No fisgonearé, así que...
Je ne lirai pas,
Não vou olhar enquanto
 você escreve, então...