anchor: Mr. Hastings, you do not think ”surely it could not have been Lawrence ”Oh, no, that could not be! But I myself was puzzled, and as soon as I was alone with Poirot I asked him what he thought Sir Ernest was driving at. 
positive: The moment Poirot and I were alone, I inquired as to his opinion about what it might be that Sir Ernest was insinuating.
negative: I never had the opportunity to seek Poirot's opinion regarding what Sir Ernest was implying.