After breakfast, and bolstered by the effects of coffee, Chen Yu also revived in spirits. Once he sorted out his appearance, he picked up his white coat and stethoscope, ready to begin his routine ward rounds for the day.
Following Keiko's father's fever subsiding last night, his vital signs had stabilized and there hadn't been any incidents all night, so Chen Yu had actually managed to get a decent night's sleep. The reason he chose not to use the "Necromantic Space" to go home and instead slept in his office was because he worried that if something happened and someone came looking for him and couldn't find him, it would cause a delay.
Sleeping on the sofa was indeed uncomfortable, but given the potential for patient emergencies, Chen Yu's actions were not at all strange.
