Kernrechtsfrage
Whether the refusal to exempt the witness from summons is an immediately appealable interlocutory criminal decision under Art. 93 para. 1 lit. a BGG.
Extrahierter Entscheid
No; the witness can still invoke the refusal right before the appellate court, so no irreparable legal harm is shown.
Extrahierte Begründung
The appellate court will conduct the witness examination itself, and the witness may assert the statutory refusal right there. Any harm is therefore not irreparable in the legal sense required for federal appeal admissibility.