Health.

When WuXin comes, he looks at him, being just as worried as TianQi for the lack of response. «There is JinYi in there, something is up with him and he might be in need of help», he hurries to say.

When the door gets opened, they find JinYi on the bed. LaNi approaches him to check his vitals and thankfully he is not dead nor in an unstable condition. He passed out from weariness, since he literally spent the two whole previous days crying, without eating, drinking nor sleeping.
At that point, though, nothing saves JinYi from a full checkup, but what he was trying to hide is evident even without needing to take his clothes off. His face is full of signs of heavy beat ups, as well as the whole rest of his body, but what LaNi finds the most worrying are the bruises around his neck, as if someone strangled him.

LaNi refreshes the medication for his broken ankle, that got all messed up, and applies some medicines that will make the bruises heal faster, plus a couple of injections.
After seeing all that JinYi went through, he can't help but fear that Hoseok could he the responsible, due to the weird behaviour QI reported and also the fact he suddenly appeared in Shiinden again after a long time.
He took pictures on his phone of the injuries on JinYi's body, to keep them as a proof for when they'll act to uncover the matter.

He leaves after being done with all the procedures.