Headscratchers / Isle of Dogs

• Why is Atari able to open the cage with the dead dog if we later find out that this wasn't his cage?
  • A Master key, just like the one Gonzo and the "cannibal" pack used. That is, a key that can unlock any cage of that particular model, and possibly others.
• Why did the cats get incarcerated alongside their owners at the end? They weren't responsible for what their owners did.

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