: That reminds me that I've always found it an interesting leap in regards to
: the Delta Halo situation where we leave it in Ghosts of Onyx, and then it
: showing up as a Flood hive in Halo 3. We know the Covenant were apparently
: fairly effective in stopping the Flood from leaving the Halo ring—but
: leaving High Charity would have been a fairly big oversight. Did they
: attempt to destroy High Charity to stop its infestation?

You would think that would be a priority, especially since the Brutes and Elites(despite being at war with each other at this point,) had formed a temporary ceasefire to blockade the Flood. Could High Charity have had it's own shields and thus been protected from the combined fire from Brute and Elite ships?

Perhaps it was build to be essentially indestructible from the outside and only small teams could crack through and infiltrate it? That would explain why we see the bodies of Elites, Brutes, and humans who were not infected or were only just being infected as the Master Chief retrieved Cortana.

I like to think that was the case and only by detonating it's reactors(or something similar) from the inside could destroy High Charity.