Twice in the play, Marie interrupts to plead with and warn the professor to stop, suggesting that these moments, from Marie’s external vantage point, are points of no return in the repeated semi-ritual of killing. The first moment is when the professor decides to shift into arithmetic, which he says, “is rather a new science, a modern science, properly speaking, it is more a method than a science…and it is also a therapy” (50). Of course, arithmetic is thousands of years old and far from new, and rarely considered therapeutic—although the professor’s increasing vigor might suggest otherwise. He begins by quizzing her in basic addition of single-digit numbers, praising her heavily for giving correct answers. This praise seems illogical and absurd for math that a young child would find simple, but the professor treats these correct answers as a sign of her ability to comprehend the logic of arithmetic. Earlier, when the professor and student discuss the weather, the professor comments that they are fortunate that it did not rain or snow. The student counters that it does not snow in summer, and the professor replies, “We can’t be sure of anything, young lady, in this world” (48).