>>723067331
He actually ran several tests.
The name game they played right before that was basically 20 questions but he didn't explicitly state the rules. There was a maximum number of questions he was supposed to ask and after that, any German would know not to answer (Kruger didn't answer as she was playing a German, Fassbender did as he was a Brit)
The weird accent, the not knowing the question game, and the hand gesture were 2 points on a graph for SS guy.