Since everyone was drunk last night they had to suffer a tremendous hangover the next morning. Thus they departed late. On their way back they decided to visit the village market as well. As a result the time they reached the pier it was already evening.
When they reached the pier Ning Tan got a call from her parents telling her that her grandfather was ill and she needs to come back home. So she didn't waste time and left for her home from there after bidding Yuerui and Yefang goodbye.
Yuerui and Yefang were left alone.
Since they came there by bus, their way back to the dorm was also bus. And it was getting darker. So they didn't waste any time and went to the bus stop.
But unfortunately, every bus was crowded with people. In order to get a comfortable journey, they had been waiting for a bus with fewer people for a long time. Later, when they were tired of waiting they decided to hop on the next bus even if it is crowded.