"How did that happen?" Samantha asked, genuinely both concerned and interested in the answer. Inadvertently her gaze dropped to his knee, well technically both knees, as she tried to puzzle over which one it was that he'd hurt. Of course there was no possible way she could ever figure that out just by looking at him, and she'd already asked how it happened. Asking which one didn't really seem like the right thing at the moment. The way she figured it, he'd probably mention it in the story.
Then, the second question his sentences had brought to mind came out without her really meaning for it to. And it was mainly because just by looking at him, she couldn't tell exactly how old he was. But she figured probably around her age, or a little older. "Are you not in college anymore then? Did you graduate already?"