So it is now confirmed that the Master Builder is indeed alive, and that knowledge of both his survival and the UrDidacts survival have been hidden from the Librarian and IsoDidact (Obviously it won't last long). And we learned how the preparations for a Halo's firing destroy any remaining organic material (Carrion, Bone etc.), which the lack there of would eventually be used as evidence in the covenant of the forerunner's divinity.

Also interested to hear Librarian's testimony on the Didact's memories of the Precursor. I wonder seeing as the transformation isn't complete will parts of Bornsteller shine through or is he pure Didact minus some memories? I hope there is a little bit of Didact left...

Well by next week hopefully we will have a basis for beginning Halo 5 speculation, or know if Silentium is merely an end cap.