And the main issue facing such a hypothesis is, what about the things that go into or come out of the wall?

Luckily the point at which we start sending conscious beings out beyond the solar system is by one hypothesis the point at which we reach a technological singularity. How a planetarium would interact with an AI, only God knows. But for things like Voyager, it's of course no problem: the superintelligence eats the Voyager, and in its place sends back the signals the Voyager would have sent back if it hadn't gotten eaten.