As for Synthesis, which I had access to due to scanning lots of shit, it sounded like a pretty sweet deal at first, when the Starchild explained it to me. Control is fundamentally sound, but too unclear as to its consequences. Even fully aware that I was dooming EDI and the Geth as well. I built this thing to destroy the Reapers, and goddammit, that's what I did. I chose the Destroy ending because, frankly, it was the only one I could stomach.