Test it in the waiting room

"Now we're going to try it. I'll call you and ask you to say something."

Gabby just waited.

"Not here, silly. I want you to go into the waiting room."

"The waiting room? But your secretary's there."

"You don't have to worry about him. Even if he does hear something, he won't tell anyone. Besides, I might call you when you aren't in an empty room, right? You're such a naughty girl, you'll pick up, won't you?"

Gabby paused for a moment, "Yes." she said slowly. "Yes I will, Mistress Vierre."

"Out you go, then."

Gabby walked out into the waiting room, and looked at the chairs. She realized that she could sit in a few places. She could sit farther away from the desk, where he wouldn't be able to hear her, a spot closer to it, where he couldn't see her, but might hear her, or somewhere she could do both. Or, another idea occurred to her as he glanced up at her, she could walk right up to him.