"…Then I'll just go back to my apartment to sleep instead."
"Weren't you feeling scared?"
"Although I'm scared, I can't have you sleeping in the living room."
"I don't have any problem with sleeping in the living room."
"Neither do I…"
"It's not the same."
Seiji didn't want Chiaki to sleep in the living room for multiple nights, but Chiaki also didn't want Seiji to have to sleep in the living room. That was why she preferred to return to her own apartment rather than having Seiji make such a sacrifice.
But, she said that she was scared, and Seiji was indeed worried about her and wanted her to stay here.
So, he decided to simply move her bed into his apartment! With his boosted physical strength as a spiritual ability user, this was quite an easy matter.
Seiji put Chiaki's bed in the study and tidied it up for her. That settled the matter.