I read and enjoyed the interlude a couple of days back - I know "Department of Floaters" made me giggle, and I grinned at the Pool showing up.
And then I got to thinking about when, exactly, HQ acquired an aquatic zone...
My starting position is that all the HQs take place in the same intersecting Cascade as, well, HQ. Digital HQ exists in our networks; Aquatic HQ is... well, an unusually wet part of HQ, which is sectioned off by necessity to avoid everything getting a bit too wet (or, in their case, dry).
Contradicting my position on methane worlds, I suspect Aquatic HQ did form during the Cascade. Maybe it came from just one portal, opening between a land area and an oceanic one, and the Weeds decided to enclose the water rather than let it flood the land canon; more likely it's a deliberately-connected zone of all the underwater portals they encountered. We could probably do some tests on salinity to figure it out.
I would imagine the area was initially abandoned, Flowers being mostly land-based. There are probably sealed doors leading there which Building Maintenance occasionally patch leaks on, without knowing what they're protecting. But when widespread recruitment from badfics began in 2002 HST, the Flowers recognised the need for an area for water-breathers, opened it up, switched on some lights, and terrorised Makes-Things into adding some waterproof consoles. Ta-da, Aquatic HQ was born.
And other HQs. The Cascade reached the entire Multiverse; for every environment you can think of, there's a cluster of corridors where the Weeds linked up all the related portals and sealed them away. Some of them are tiny, only a room or two; some of them are colossal, almost matching "normal" HQ. Some of them are in use, like the High-Pressure HQ formed mostly from sci-fi super-heavy planets; others are empty, waiting for the PPC to recruit enough agents who need them and can't be accommodated in the standard areas.
By and large, the occupants of the different Zones keep to themselves; most in "normal" HQ don't even know the zones exist. There are, naturally, numerous conspiracy theories about why this should be so; pick up the next issue of the REAL Real Multiverse Monitor to learn the TRUTH!
hS (with a little interference from Starwind and Estelnar)