During the almost ten hours of Shoah (1985, Lanzmann), the landmark documentary on the Nazi extermination of the Jewish population, there is an episode that stands out. What accounts for its memorableness within a memorable film is the rhetorical procedure of aposiopesis. A semiotic analysis of this sequence helps us understand the process whereby a visual representation of the verbal witnessing of atrocity produces an unparalleled experience of those appalling memories through silence. Curiously, Shoah omits all images of historical evidence to focus on the words of survivors, of those who lived to tell the almost untellable. Peirce’s phenomenological categories of experience, the basis of triadic semiotic (e.g. iconic, indexical and symbolic) serve to describe the process whereby the testimony of the sole surviving slave barber of Treblinka traverses three narrative stages. There is the indexical basis: Abraham Bomba’s embodied testimony in the film as undeniable evidence of a genocide whose magnitude is hard to imagine. His startling verbal account: the outpouring symbols which give us a detailed account of the prologue of the heinous crime. Lastly, the iconic instant which occurs when this talkative barber seems to run out of verbal steam. It is then that he chooses not to tell what he tacitly expects his interviewer to imagine, though he knows this is an impossible task. Rhetorically, aposiopesis cuts the story short and makes an uncanny, unvoiced invitation to the audience of his testimony. How could he/anyone communicate what could not be told to the soon to be exterminated victims all around him? This use of aposiopesis is a necessary narrative strategy for telling about the unimaginable, about that which exceeds the limits of the human body to bear and transmit, but which is essential for humanity to imagine and grasp.