They only saw the two artificial hills flying towards the room doors of Sun Yixie and Huang Donglai like missiles, accompanied by two loud 'bangs,' shattering the doorways as if they had been hit by gas cylinders.
However, the result was that there were neither ambushes nor traps within those two rooms.
Gu Qiying and Shen Youran stepped in to take a look. Huang Donglai's room didn't have much in it, you could tell someone had lived there and the useful luggage had already been taken away; but in Sun Yixie's room, something indeed had been left behind.
It was only after they entered the room and saw the light from outside that Gu and Shen could see clearly...
Before leaving, Sun Yixie had written a line in ink on the wall of his room, using a few simplified traditional characters that he knew, which he found relatively easy to write—Are you two feeling a chill down below?