Don't know where I picked it up, but something indicated to me that inside R_eh = 2GM/c^2 lies a black hole whose R_bh = GM/c^2. And that at R_bh lies the energy singularity. And that at R_eh there is not an energy singularity, but only an end to communication with the world outside. I know that outside observers cannot detect what is inside the event horizon sphere, but that should not stop the mathematics from predicting what is going on in there. Especially since authors(wiki) say that nothing in particular is experienced by an observer passing through the event horizon. The "mathematical breakdown" seems only to be a "communications breakdown" in other words. Mathematics predicts stuff we cannot see...like the "dark properties"... What's the problem here? Is quantum mechanics going on in there?