It is smart that she is taking some control of the 'situation' and maintaining some leverage.

"Are you simply the courier, or do you profit from the sale also?" Skellig asks straight up, blunt and matter of fact. He knows he will not like the answer given regardless of the response, and it disgusts him slightly to even be having this conversation, even if it is hypothetical...

He needs to know if this is the middleman or the actual one who will gain the most from the sale of these people.