C121 To rediscover a clue as a title

I didn't even have time to think about it, from the time I left the clinic, when my friend Chen fainted from hypoglycemia to the time it took me to get out.

However, what I didn't expect was that the moment I left the room, I heard a sound behind me. That nurse actually closed the door.

At first, I didn't pay much attention to it, but as I thought about it, I realized something was wrong