You can actually pinpoint the moment that Nessa realises that the woman is actually far more fascinating that previously thought (not that having a doppleganger from another world wasn't already fascinating). Her eyes widen in wonder as he brain went through every plotline of every story she'd read that involved cryogenics before realising she'd gone on a tangent and Karkat had said something else.

She tilts her head and watches him carefully, sensing his nerves, and instinctively shuffles toward him.

"Your ancestor? Did she... recognise you?" she wonders aloud, frowning at her own question. "But how come we..."