Why use it as a way to activate every Halo? The comic made it unclear as to whether the Ark was built before or after the Forerunner were terminated by themselves. Did they all activate the 7 Halos in unison, or did they get their Ark built and have some protocol initiated by N'Chala or some other chosen human? Which also begs the question of when Onyx was built, or when any of the Halos were built. Were these things made pre-Flood, during-Flood, or post-Forerunner? If they activated all 7 Halos together and then left blueprints behind for their robots to follow just incase something crazy happened again in the future, that'd make sense but still seem odd.
Exactly! Why study and contain the Flood? Master Chief's shotguns work well on those suckers. I'm sure the Forerunner had equally capable weaponry, and killing them one by one couldn't have been very hard if they were confined to certain spaces all together at once. Either the Forerunner truly were very stupid, or boy did they mess up with their own containment protocols. The monitors are all about containment, but it seems like "every last option" that they exhaust are minimal at best at containment. In all the time it must have taken to build Halos, Shield Worlds, and an Ark, how did they not manage to find a way to exterminate the Flood instead of themselves?Why, did the forerunners put so much effort into building a weapon that would wipe out the Flood's resources instead of putting a bit more thought into creating a weapon that would wipe out the parasite itself?...
I hope this "Iris" thing gives us some insight into the thoughts of the allegedly most advanced race in the galaxy's history, because right now a lot of their stuff seems pretty flawed. I'd personally like my opinions to be wrong about the Forerunner. I'd like to think that they had some idea of what they were doing.