"Sick? You truly are incompetent," Diavolo murmurs as he brushes his cold fingers against your feverish skin, the faintest soft look in his eyes giving away his worry despite his stiff tone and stoic expression. "This is exactly why I ordered you to stop working so much overtime."
To be in the room of his sick assistant after hours was rather out of character for him. So out of character, in fact, that he finds it almost unsettling. This is only because you have work to be done, he thinks decisively to himself, excusing this moment of weakness. I couldn't care less about her well-being at all.
He finally clicks his tongue as he pulls away from you. No, this won't do at all. He couldn't possibly get weak over a mere assistant. To be plagued by worried thoughts of you ever since you sent a barely coherent email explaining your sickness was simply unacceptable. A weakness he must never allow.
Perhaps it's time I get rid of you, as useful as you are. How annoyingly useful and pleasant you are.