Walter Kantner: Pardon me? I am the fiancé of Miss Bercelius.
Hanni: Rules are rules, who doesn't check in properly won't get a room.
Felicitas Bercelius: Don't make any trouble, Stinker.
Hanni: Is this the first name?
Walter Kantner: What?
Hanni: Well, Stinker.
Walter Kantner: Walter.
Hanni: So it's Walter Stinker.
Walter Kantner: Ingenieur Walter Kartner.
Hanni: Who's ...
Earlier Dr. Kellermann named Gustav Kellermann, according to the letter read by Pitzelberger to Hanni and his colleague. However later when Kristian gave a fake name to Hanni at the reception, calling himself Dr. Michael Kellermann, she is frightened and mistakes him for the actual Kellermann, even through they had a letter with the actual name. However this could be deliberate as it was said in the movie that Dr. Kellermann wants to study unremarkable and they don't want Kellermann to come here.