Text: The most devastating rebuttal is from the chemist in charge of the Auschwitz analysis, who explains that the gas wouldn't have penetrated more than 10 microns into the wall (a human hair is 100 microns thick), so by crushing the samples (standard procedure), he had effectively diluted the cyanide 100,000 times.
Entailment: The chemist in charge of the Auschwitz analysis gave a devastating rebuttal.
Contradiction: The chemist crushed the samples and diluted the cyanide 500,000 times.