What is marguerite's dilemma at the end of chapter 8?

The Chauvelin wishes her to help France by assisting them in their search for the Pimpernel. Marguerite says no, but the Chauvelin says that they will meet in London.

“That is beside the question,” she said at last with indifference. “I can defend myself, but I refuse to do any dirty work for you–or for France. You have other means at your disposal; you must use them, my friend.” And without another look at Chauvelin, Marguerite Blakeney turned her back on him and walked straight into the inn.

“That is not your last word, citoyenne,” said Chauvelin, as a flood of light from the passage illumined her elegant, richly-clad figure, “we meet in London, I hope!”

“We meet in London,” she said, speaking over her shoulder at him, “but that is my last word.”