In this passage, there are a few literary devices used. One is the use of hyperbole, as the speaker describes the punishment for saboteurs as "the most horrible thing you can imagine" and refers to the Germans as "fine specimens of humanity." The use of hyperbole serves to exaggerate the speaker's feelings and thoughts about the situation.
Another literary device used in this passage is rhetorical questions, as the speaker asks, "And to think I'm actually one of them!" This rhetorical question serves to convey the speaker's disbelief and shock at the actions of the Germans.