Liang prepared breakfast for Kristina, Nathan and himself before leaving for work. Nathan is already at the dining room, eating; Kristina did not come downstairs. 

Is she alright? Liang can't go and ask her now cause the carpool is about to arrive.

Well, the carpool is here, Liang thought Kristina was probably still asleep, so he just left. He's sure she's fine, he'll talk to her when he returns.