Barring any limitations of my understanding, the Mythos model weights are probably in the realm of a few TB. Any actor with access to the weights + a single beefy NVIDIA cluster and a few intelligent folks is all it takes to gain access to Mythos.
Cost of infra < $5 million (guesstimate). Imagine someone pulling that off by gaining access to the weights - which would be a monumental challenge, but likely less complicated than re-acquiring enriched substances from the gulf nation under attack right now. It would be the heist of the century.