Panel interviews for engineering roles in Germany often mix a technical lead, an HR partner, and sometimes a future teammate. The technical lead wants decision quality; HR wants communication and reliability; the teammate wants to know how you handle disagreement.
Prepare three stories that each open with the decision, not the project kickoff date. One should cover a conflict with cost or schedule. One should cover a quality or safety catch. One should cover learning a method or standard under time pressure. Keep each story under two minutes, then offer depth if asked.
If the panel switches to German mid-answer, it is acceptable to finish a sentence in English and confirm understanding. Clarity beats imperfect fluency when safety or tolerances are on the table.