Pretty sure this guy is Blaze trying to peddle the same garbage Siriel does in SB about how it's possible to reach the planet's Inner Sea/reverse side by simply digging deep enough into the planet. The argument is that since that's something Albion tried to do, it should be possible in general. I find the argument itself highly disingenuous since it requires you to disregard everything known about the properties of the Inner Sea, the main of which being it's a dimension only non-physical souls can go, something that's very well established in Apocrypha and GoA. Albion is also a bad example, since Albion's body itself follows different physics, hence Albion's Tomb and the Ancient Heart in Case Files and LB6 being shown and stated to be on a different layer of reality following different physics from the rest of the texture. Along with Albion being the dragon of the boundary, and the implications of it being the actual gate between the AoM and the reverse side of the world.
There is also the fact any path to the reverse side was closing through the passage of time, with only some fairies being able to enter and exit by the time of Camelot (and only because they can survive as spirit bodies), and even that path was stated to close in due to time. In the past and in it's desperation Albion tried to dig through a gigantic leyline still connected to the reverse side and it's corpse fused with it after it died. Even if there were other leylines connected to the reverse side in the modern era, if Albion couldn't make it even with that it's pretty much impossible.