For starters, no hunter was letting her do anything. If anything, perhaps the hunters she knew could thank her for not snapping Dean Winchester's neck when she first met him in York and he insisted there were no good vampires. She'd enjoyed giving him that beating.
Though she was not directly fishing in Cas's head for information, now she was on edge, and would soon begin to do that. Any of his methods of harming her would prove ineffectual at best and likely only serve to anger her.
Then there was the issue of hiding.
She'd never hidden what she was. In fact, a few very unlucky individuals had the pleasure of meeting Saerian. She thought of the devil's traps Sam and Dean had put outside Harry's house, and smiled very slightly.
Phaedra processed all of this in a few seconds, then reacted.
The vampire rolled her eyes, which were beginning to bleed to their more feral, annoyed level of green. She took a few steps toward Castiel, smiled, and told him all she needed to using only her mind.
I'm not in the least obligated to answer your questions, gadje.* Leave me alone or you will regret it, I promise you.
*literal: outsider; used as a blanket term that means something more like 'punk' or 'idiot.'