It seems the Empress and this eunuch are both trusted by the Emperor, so while others have withdrawn, these two were tacitly allowed to stay by the Emperor.
As the Emperor dismissed everyone else, his face didn't look well, although it never really did. The Emperor is not an idiot; he can sense that there's something unusual about his illness from Ye Shuangshuang's behavior.
If it were just a common illness, there would be no need to avoid other people, unless his illness was abnormal.
Once the palace maids and eunuchs left the room, Ye Shuangshuang didn't speak of the illness, but first asked the Emperor, "Your Majesty, may I ask if you've been consuming some unique tonics since half a year ago, resulting in mental and physical health improvements?"
The Emperor was taken aback and nodded, "Indeed, I have been consuming a health supplement since half a year ago, but it is not one of the Alchemists' Elixirs. I'm sure I haven't been poisoned by one."
