Could you just find out when the gate to the outside is shut by looking at various people in the inverse fire? If they aren't present then the gate would be shut in their lifetime, because they wouldn't be in the eternal torture machine/hell. After all, the inverse fire says that if they are there they were always there.
Because otherwise they'd both be in hell but also not in hell - the gate is shut but also they are in hell and always have been? Or is that the kind of mismatch between reality and meaning that unbinds a meaningful universe?
