She blinked at the smile, and couldn't help but return it, before he asked the inevitable questions. She ran through a quick explanation for him, much like she'd done a long time ago; she explained about the lab accident that let them know about the Map that they all worked to, and how they needed stem cells in order to create the tailor-made viruses, and how the changes were made. "And yes, it made you sick, both times. It's how a virus works. I'm sorry."