[quote=@BBeast]
If Jvan disappears, she said that the Gap would flood into Galbar.
[/quote]

Correct (at least, soon)! 

Just for everyone's records, though, that wasn't always the case. As with other codex contributions, the Gap as a whole is quite stable even if Jvan is gone, so long as it's left alone. It's just one particular major Gap pocket on the surface of Galbar that's (as of upcoming events) dependent on her survival.

So the universe and the other gods might not be too badly off if Jvan died. Ten billion mortals, though, would be a little upset.