The hands tightened round her neck, the room whirled, blackness, spinning blackness, suffocation— everything going dark… And then, suddenly a cough. A prim, slightly artificial cough. [...]
Just inside the door, Hercule Poirot stood apologetically coughing.
‘I hope,’ he said, ‘that I do not intrude? I knocked. Yes, indeed, I knocked, but no one answered… I suppose you were busy?’
[quote redacted to avoid spoilers]