Perhaps I was unclear. No one real world line enters into this region. The singularity itself is different. I think the problems with the singularity will only be resolved with a quantum theory of gravity. There's quite a bit of spacetime between the horizon and the singularity.
Disconnected universes are different from insides of black holes.
Let a very reliable physical theory predicts such an object. Suppose you have just fallen from a 100 storey building. In principle, you will die in moments. You will never observe it.