In Die Hard Gruber tells Karl to “Sheiß den Fenster” (which he then clarifies in English to Karl who would have recognised the command when Gruber gave it.)

The correct term would have been “Scheißen Sie auf das Fenster”.

Gruber isn’t German at all. And maybe Karl knew that, hesitating after the command- “Do I correct him or do I…” before Gruber speaks again