If you went into a black hole would you end up in another dimension?
Actually the world inside a black hole is regulated by the same laws of the word outside it.
The difference is that the gravity is very strong and all the relativistic effects are more evident, also the fact that the light cannot escape.
But the fact that a black hole is a portal on another "dimension" (whatever it means) I think is more sci-fi than physics.
There is a theory that says that the total mass of the universe would create a black hole with more or less the dimensions of the actual universe. Then maybe we are in a black hole right now.
But I never read the calculations of this idea, so I do not know if it is a urban legend among physicists or a real estimation.