I’m assuming the automatic translator got it wrong, and it’s not a noun, but a verb: packen. But then does the translation into “Get away!” mean, 'No, way!," a negation rather like “doch,” or does it mean more literally, something like “Pack it in,” or quit? These little colloquial imperative are very puzzling.
It just means “Get lost” / “Scram” /“Hit the road” (I am deliberately using translations which would cause the same problems the other way round )
Maybe a very short form of
“Packe deine Sachen (und dich selbst ) zusammen und verschwinde.”