We see Agartha every time the collision fails and we appear inside the planet
The gravity drags us towards the center, though.
Seriously though, it could be possible, although several things have to be handled. Nothing very complicated I suppose - tile-level culling, and all the normals inverted and so on.
While doing this on Earth doesn't make sense, this reminds me of
Dyson sphere and Ringworlds, this is something we'd like to try one day.