"You mean to say he might have become mad deliberatelyT' said one in an incredulous tone. "

In an incredulous tone from a man beside Rose Jordan.

He says this in a tone almost incredulous.

"It shouldn't hurt," she said in barely a whisper, her tone incredulous.

And then, in a slightly incredulous tone, "Not White's office?"

And then, in a slightly incredulous tone, "My eyes?"

Banker, in an incredulous tone: "What's the name of this business you run?"

But the incredulous tone is merely the most obvious of the show's peculiarities.

Rain couldn't keep the incredulous tone from her words.

Why is this written with an incredulous tone?