[pdonis]

> spacetime inside the black hole flipped around, where space becomes temporal dimension and time becomes spatial dimension

No, this is not correct. The "flip" is in a particular choice of coordinates, not in spacetime itself.

> time is traversable in either direction while the singularity becomes an inevitable place in the "future"

It is true that the singularity is inevitably in the future--that's because inside the horizon, the future "time" direction points towards the singularity. But time is still only traversable into the future; you can't "reverse" your travel in time inside the horizon.