Well, not necessarily literally their smell. It could be a figure of speech.Little conspiracy theory but:
-New humanity recognizes human by their smell
-The girl covered in bandages from their world before their mission gave them a hug which came out really out of place
Maybe she intentionally rubbed them the smell that the New Humanity could recognize
But yeah, with that whole spiel about how the Neo Humans love to let humans think their plans are working until they crush it, Haji (think that was her name) has got to be one of them.