According to her words, the reason of her absence was because she had a headache or abdominal pain, or the communication with Isshiki : 'I have to communicate with San during the day.'
When Saori told Kyoko that she had a headache or abdominal pain in her bed before going to school and asked her mother Kyoko to call the school on account of absence for illness, Kyoko saw how she was. Certainly, Saori looked pale and seemed to feel ill.
She seemed to have stayed up untill late, last night. Kyoko wondered;
Did she contact Isshiki?
Did she write any novels or poems or draw illustrations?
Does she hate school because of bullying?
Kyoko called the school and told about Saori`s absence, adding a possibility: 'Later, when my daughter gets better, I`ll take her to school .' to the message. But mostly on such days, Saori did not go to school.
In the case of the reason being that Saori would communicate with Isshiki, Kyoko did not want to agree with her. She thought that it was so wrong that she could not accept it, but against Kyoko`s will, she called school about Saori`s absence because of illness.