Even if he did attempt to probe deeper, Regan wasn't worried. Her mind was intricately designed for just that possibility.
Inside Regan's mind, the first layer had been constructed like an English Baroque mansion, surrounded by exquisite gardens. It was an illusion she'd spent years crafting, and it was incredible in its detail. Every room was where it was supposed to be, and even opened--there were no locks. Visitors could sift through her knowledge of the Crimean war, or find the room entirely dedicated to Cosmo magazine. It was airy and open, but void of any real depth.
All of Regan's real mental processes were hidden, tucked into nooks and inside the most unsuspecting objects. The mansion on the surface level was linear and whole, but there was no reason Regan couldn't hide an entire dungeon inside a teacup, or on a certain grape in the hand of a certain statue.
She'd defended her mind not through powerful, impenetrable wards, but through clever tricks. Even the most powerful telepath wouldn't be able to tell which painting in the gallery contained Regan's loyalties. Every stroke on every painting was illusion, so that nothing stood out as more concentrated with telepathic energy. Unless a person knew exactly which illusion hid a door, they'd have to tear the whole thing apart, piece by piece, risking triggering any number of mental traps Regan had built into her illusions--or rendering Miss Wyngarde catatonic, if they succeeded.
When Kurt returned, she smiled at him, relieved. "I was scared you were going to come back with a whole arsenal pointed at me. Um." She pointed at her head, sheepish. "Mr. Xavier said you'd show me in."