Juturna's Time Direction

(apologies if this appears twice) In UOTNS, Juturna sticks her head and arm into the throne room. Severian asks her if she remembers saving him. She says she does not, that it has not happened yet, but that she will (save him, presumably) since he has spoken. This suggests that Juturna is running backwards through time similarly to Ossipago, Famulimus and Tobedwego (can't remember that last name.) Severian thinks Juturna is dying, crushed beneath her vast weight, but when the throne room is flooded, she gives a cry of triumph. Presumably, the flooding may wash her into deep enough water that she lives. So, it seems like Juturna is moving backwards in time, survives her suicidal entry into the throne room, and saves Severian from drowning. I hadn't noticed before that Juturna was one of the backward-time characters. Am I barking up the wrong tree here? Also, in UOTNS, Idas says she is as human as he, one of the people of the lords of the ocean and underground. If creatures like Erebus, Abaia, etc. are also underground (which I had never noticed before), they may survive a flood. They must be smaller than the underwater people, since without the support of the water, they would be crushed by their own weight. Any other mentions of these underground lords that Idas is talking about? -Brian

Brian asks-

Erebus might be associated with Mt. Erebus in Antarctica not the ocean. And I always thought the presence Severian disturbed in the mine near Saltus was a Megatherian. -bsharp

She seems to have several conflicting motivations; at best, I think we can agree she is happy because the struggle is out of her hands for the time being, she can reast, having "only" the flood to deal with, which would be relatively easy for a time-traveling water-breather.

It may not be suicidal; she's bleeding and such, but a being of her size can take a looong time to bleed out.

Her dialogue and her ability to point into the 5th dimension indicates she skips around, just like Severian.

If mobility can be sacrificed, an organism can be supported by earth and rock just as well as by water. Megatherians may also be less than completely biological, they could be evil versions of The Ship Who Sang or The City That Fought or even Zardoz! They may survive a flood without being able to survive The Flood; the White Fountain produces huge tidal stresses on the Urth, flooding and re-flooding the land twice a day for several days with potential flood heights peaking in the middle. The land also undergoes lesser tides being less flexible, but the larger the land feature, the larger the total tidal force applied; if those add up to a sizeable crack, in comes the flood water!