"No, not exactly."
Ian was very clear that the 'Dark Key' of the Thousand-Star Beast was likely some kind of last resort similar to Terra's Dead Hand System. Without the Empire's presence, Terra would have no reason to exist. They were truly crazy enough to press that button.
Therefore, when Marquis Barton suspected that Ian had 'prophesied' the existence of the Thousand-Star Beast, he couldn't help but be shocked by such a future—could it be that the Empire had lost to such an extent that it would drag the entire world down with it?
It's just like Earthlings knowing their future involves pressing the global nuclear button: shocking, yet not entirely impossible.
Even if the Dark Key couldn't destroy Terra due to the intervention of the Four Great Orthodox Churches and other factions, dragging hostile forces like the Fiery Flame Land, Azure Sky Royal Court, and Steep Ridge Fortress down would certainly not be an issue.
"That's good."
