This is just the reading comprehension of the coper. They say one thing, get exposed, then move to the next. The next thing will be ‘okay, the sky is flooded but it doesn’t prove the universe was!’
That’s when we go back to this panel.
They will then proceed to tell you ‘well Reiokyu is just in the atmosphere!’ Putting aside how stupid that is, let’s go with it.
If Reiokyu is in the atmosphere, and it got flooded, that means the atmosphere got flooded AFTER the dome closed.































