No, stay. Outside information isn't necessarily a bad thing; in an uncontrolled environment, it's likely that there would be other distracting stimuli. It would be better if you stood somewhere that I can't see you, but you're not the one I'm worried about. You don't "sound" different; it's Hierophant-kun that's likely to bias the results.

[She pauses, momentarily.]

And if you stepped outside the room, you'd just use him to observe what I do anyway, wouldn't you? So that'd be more disruptive to me than the alternative.