Text: And, anyway, I said, with increasing coldness, "as Mrs. Inglethorp took her coffee upstairs with her, I do not see what you expect to find, unless you consider it likely that we shall discover a packet of strychnine on the coffee tray!" Poirot was sobered at once.
Entailment: Poirot quickly came to his senses.
Contradiction: Poirot didn't buy it at all.