: I prefer the idea that the array uses the Flood's telepathic ability to
: destroy sentient life and the the Flood's sentient stage, communal mind's
: biomass. Perhaps the Forerunners perfected the mechanism so that the Flood
: biomass that's used to generate the pulse isn't, itself, destroyed.

: It's all that neural physics stuff that Bear mentions in his books.

: Or more mundanely, in the specific instance of the tactical detonation of the
: ring at the Ark...

: maybe not all the Flood was on the ring. The detonation, "did a number
: on the Ark" but didn't completely sterilize the surface.

: The most cynical answer is, they need the Flood to have survived in order to
: have this DLC, therefore the Flood survived. It's like plot armour.

Well, the idea that all the active Flood were wiped out in H3 in the first place was a pretty bit contrivance ("uh, Gravemind just gathers all of its forces together when it's threatened!")