Given this announcement the prisoner can deduce that the hanging will not occur on the last day of the week. However, in order to reproduce the next stage of the argument, which eliminates the penultimate day of the week, the prisoner must argue that his ability to deduce, from statement (A), that the hanging will not occur on the last day, implies that a second-to-last-day hanging "would not be surprising". But since the meaning of "surprising" has been restricted to "not deducible from the assumption that the hanging will occur during the week" instead of "not deducible from statement (A)", the argument is blocked.