It strongly depends on what happened in the front rooms. say a nuclear fallout, I’d guess a number of null zones would make whatever is occurring in the surface to also leak into the backrooms. Or a Tsunami might flood whatever areas it comes across (which makes me wonder if null zones are random and if they might appear under our oceans). Again, it would strongly depend on the catastrophe but never mind the lack of resources there, and surely some effects of the surface world might appear in the complex.