Confusion

She might not have seen her sister for a year now, but that doesn't mean her appearance will change immediately for her to not recognize her sister. So seeing her from the crowd was a sudden surprise...and in the middle of the execution of their parents no less.

The one who looked like her sister wears a hooded cloak, hiding a bit of her face, but Elaina can still see her face and she cannot be wrong on this one. That is her sister, no doubt about it.

Elaina felt the urge to shout and call her sister but she also realized that is not an ideal way to reveal herself in the crowd. So instead of calling her out, Elaina went herself and waded through the crowd and tried to reach her sister in the process.