Poirot wished her good morning with Gallic politeness, and went on: "We have been looking through that chest, Dorcas. 
Poirot was very rude to her because he was busy talking about a murdered man. 
mnli hypothesis: Poirot was very rude to her because he was busy talking about a murdered man.  premise: Poirot wished her good morning with Gallic politeness, and went on: "We have been looking through that chest, Dorcas. 