Let her get captured.

The depantsed thief blushes as one of the fat noblemen lays a hand on her shoulder. "You're caught, missy," he growls, in the most authoritative voice he can muster. "Off to the stocks, then. Lorenzo, go and fetch the guards."

The other fat nobleman huffs. "Why do I have to fetch the guards? Can't you fetch the guards?"

"I'm holding onto this young lady, Lorenzo. We have to make sure she doesn't escape."

Lorenzo gives a pained, lecherous grin that tells you all you need to know about what is going on inside his head. "Well, can't I hold on to the young lady?"

While they're squabbling, the thief is fiddling with something behind her back. It's a tiny knife, so small you can barely see it. She's trying to cut her hands free.