"But...I remember taking the airships, and the coronation. We were all there. How could things keep happening if time's frozen?" She's frowning at him now, brow knit in confusion. "Is this some kind of joke?"

It's hopeful rather than accusatory. Even if this place wasn't clearly somewhere she's never been before, she knows this isn't Sokka's style of joke. But a bizarre prank would be far easier to wrap her head around, and far less daunting than dealing with friends - and enemies - whose memories may not match her own.