There was a difference between taking it and it being necessary, Akiha. And Sion was more than certain that this conversation could only result in more pain for her. Especially if Akiha wanted to show off how much supposed pain Sion could take before she decided to buckle under. Which meant that she needed to cut it off.

"Please pay more attention rather than arguing about something silly."

While she said that mentally, she made sure Cloud could hear that just fine. Which was a reminder that Sion needed to pay more attention too or else Akiha might get blindsided again.