If he could restrict the flow, he would. Sam just wasn't entirely certain about how that worked. He'd never had someone invade his mind before. Frowning, he stood over Elisabeth as she set to work. She was right about one thing -- he didn't notice that his mind was being invaded at all. He felt perfectly fine. Nothing was off at all. He slowly moved to take a seat in the grass, his attention entirely focused on Elisabeth until, seemingly out of nowhere, a voice erupted inside of his head. He instantly jumped up in surprise.
"Uh, okay," Sam said, brow furrowing in confusion. He shook his head, then stared off at Elisabeth. He had to block out any memories that he needed to keep to himself. Starting with Dean's death. That was the one that he kept the most hidden. It was personal, private, and certainly something he'd rather not share with the world. So instead Elisabeth probably ended up sifting through smaller things. Him, as a child, holed up in a hotel room with Dean, unknowingly waiting for their father to return from one of his 'business' trips. Sam reading through a book, Dean distantly questioning him in the background. Sam in his teenaged years, learning how to properly clean and load a shotgun at the hands of his father. Small memories. Important to him, but not nearly as private as those that he fought hard to keep within. Which, Elisabeth may have noticed, happened to be a lot. He wasn't being very cooperative on most of the contents in his mind.