Mable was working the angles. When you call in an expert for their expertise, you let them do the damn thing. When the fish got there, she happily met them at the front, smiling to the bewildered door dasher. She tipped them ridiculously well for this. The look on that poor man's face though when he realized he was delivering fish to a fetish club: Priceless.
She came back with the fish, but held back, letting Mable tell her when it was time. She now had the leverage literally in hand. Quinn hoped it helped their little friend change allegiances at least temporarily.