It is still difficult for me to describe, even at a distance of several years, the effect those words pronounced by that voice and in that setting had on me. It was not that I exactly understood, in any intellectual sense, what was transpiring in that cheap upstairs room. A kind of physical apprehension, almost an animal sensation of danger and fear raised the hair on the back of my neck and icy fingers of dread closed around my heart. I knew that if I did not get up from that spot and flee this place of evil, some calamity would overtake me, and my life would be forever altered. But I also knew that for all his assumed levity and studied indifference, Holmes was in desperate danger. And I could not abandon him. Not even to save myself from whatever terrible fate was hovering in the darkness above me.