The Yu Family indeed owes the Shangguan Family a favor, and now is not the time for disputes.
"The young lady of the Shangguan Family belongs to the Shangguan Family, not any other household. The lives and deaths of any other family have nothing to do with our Shangguan Family, and likewise, the Shangguan Family's affairs are none of your concern. So, with no kinship or obligation, why should our girl be expected to sacrifice herself to save you?"
"Why? Those of you who spoke so self-righteously about having Shangguan You exchange places with you, the Shangguan Family will one day seek redress."