In Chapter 14 of "The Princess and the Goblin", it is not explicitly stated who jumped into Irene's room from the window. However, it is implied that it was Curdie who did so, as he had been watching over Irene and had promised her that he would protect her. Furthermore, he had previously climbed into her room through the window in order to warn her about danger. Therefore, it is likely that Curdie was the one who jumped into Irene's room from the window in Chapter 14.