Why did he built his Museum/Monument to Amarout in The First instead of the Source?

I have known the Sources is not equal to the "world before" and that eventually if their plan of rejoinings were to reach it's end even The Source itself would go through extreme changes (more than any calamity) to be made whole.

Yet considering a similar fate. And that anyway Reflections ARE rejoined to The Source.

Why built his "work" there?

Why also we find remains of Amarout and the Unsundered in The First instead of the Source? For someone so fixed on how Reflections are less in all ways, shapes and forms from the Unsundered how does it fit that he makes his "monument" in a "lesser Reflection"?