If he could sense her misgivings from the cacophony of thought coming out of her mind, he might work at reassuring her. He doesn't doubt that this is dangerous, but he's spent a lot of time around River, dedicated enough to understanding her that he knows inherently that he will be quite safe.

So he shifts until their knees touch, something of a comforting gesture, and lifts his hand as though to touch his temple. Catching himself half way, Charles has a moment of disconnect. It was River who told him that this was his tell and he'd been meaning to fix it, hasn't he? So when his words next come they come to her telepathically.

If this hurts in any way or worries you, tell me.