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.
Hold her back or expel her, 
one of the two.
Entweder ausbremsen 
oder sie der Schule verweisen.
Lo hacemos o la expulsamos, una de las dos.
Es eso o expulsarla, una de dos.
Je ne vois pas d’autre solution 
que le redoublement ou le renvoi.
É reprovar ou expulsar. 
Não tem outra opção.