"I just have this feeling, I'm not sure," Song Yan confessed.
"Why?" Yang Xiao asked.
"I don't know, it just feels like we escaped too easily."
"Yu Mi is staying separately from us; if that ghost really comes, the likelihood of Yu Mi being attacked is much higher than for us," Yang Xiao analyzed. "What we need to be wary of is that, if Yu Mi is killed, the ghost might disguise itself as Yu Mi to trick the two of us. The moment we open the door, we won't be able to escape our fate."
"That's exactly it. If we leave Yu Mi behind, once the ghost comes, we are likely to face it directly. To be honest, I'm really a bit scared," Song Yan admitted with a bitter smile.
When facing absolute danger, abandoning teammates or using them as a shield is a very normal choice; this is very common in the Nightmare World.
The reason Song Yan chose to save Yang Xiao while abandoning Xiang Xiaolin was because he valued Yang Xiao's abilities.