"You've still got some kind of guards you left back there," she points out. "Which says to me you've still got some kind of importance. Enough for people to think you're worth guarding, anyway. But you still leave them back here and come alone, which either means you don't think you're valuable . . . or still have some moves as an old guy."

Frankly, she's curious -- mainly what he thinks of his own importance. She doesn't know much about this older version of him except for the glimpse she had when they met. He seems . . . imperial, remote. These traits nudge her to stay away; if he's become an adult, if he truly does have that level of removal, he may be far too like her parents for comfort.

But seismic sense nags that he's Zuko. Somewhat weird, not-quite-right Zuko, but still Zuko. And for that she can't quite stay away until she understands what she's dealing with.