AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING AND THEY DON'T STOP COMING...
Fun fact: Apparently Index can refer to a list of restricted or prohibited material, the reading of which was prohibited or restricted from Roman Catholics by church authorities. Given how much religious symbolism is in this game both for good and for ill (John-117 is your main character for cryin' out loud) that might be what it was referring to.
Although I personally assumed that it was called an index because the activation codes for this superweapon were so complex and long, and the Library was full of different codes and protocols, this was just the relevant one for firing the ring.
"The DM has decided that we have gone off the rails"
Yes
Like
I understand what's going on and can make guesses as to why GS didn't teleport you directly to the index (his programming probably prevents him from getting you any closer) but that's partly because I've played the later games and understand what the index is for. It's pretty easy to tell that activating this ring is meant to contain the flood outbreak in some way, but unless I missed something I don't think this game ever explained that it's the ACTIVATION index for the Halo ring. IE the launch codes for the weapon.
And if you don't know that until AFTER the Library this feels like a complete slog for no reward