It took his brain all of three seconds to process the vision in front of him. "Theo!" he yelped, and launched himself toward her. His arms went around her, because he craved the closeness. She wasn't Nell, but he was still closer to her than to Shirl or Steve.
"What? How...why? Are you really here?" He was very aware this vision of her could be a hallucination, despite how real and solid she felt in the circle of his arms. He hallucinated things, and people, that weren't there, all the time. Half the things he remembered were probably not even real, sometimes he couldn't tell the difference at all.
"Theo?" he said her name again, and pulled back, hands gripping her shoulders. As long as there was material between his hands and her skin, she wouldn't pick up anything too intense. The fact he was worked up, and little more than a breath away from a panic attack was something anyone could see, if they looked.