Considering they had all had quite a bit to drink, and hadn't eaten any main dishes, Shen Mingzhu made a pot of vegetable congee in a ceramic pot.
After the congee was ready, Shen Mingzhu specifically served two bowls, to take up to Yan Su and Han Zibin upstairs.
Han Zibin's room was near the stairwell, which Shen Mingzhu attended to first, but upon entering, she found no one there.
...
After Yan Su had finished washing up and returned to her room, she was inevitably shocked to see the person lying on her bed, yet the personal items on the nightstand indicated she had not entered the wrong room.
Therefore, it was the person in the bed who was misplaced.
She hesitated, debating whether to pack up her things and move to the next room, or to have Han Zibin, who was on the bed, removed, when suddenly footsteps echoed from the hallway, causing her to subconsciously close the door.
Why did she close the door? Now, that really couldn't be explained clearly.