Lan Tian follows the woman all the way to the hallway where he first arrived. The disoriented look never leaves her clear eyes.
It's only after Lan Tian hears her say "Oh the water!" again, that he realizes she's stuck in a loop.
He follows all her movements as she draws the pump, complains about the amount of water, and then draws some more from the atmosphere.
Could that be the explanation for the drought in Nanpei? The time from the woman discovering her lover's corpse, to drawing on water for the fountain is very short, no more than ten minutes must have passed.
If she's going through these motions every day, for who knows how long, it can explain the depleted state of the lake.