You feel your fins shrink and your tail split back into legs. Your chest shrinks back to normal and your female plumbing becomes male again.
As you surface in the pool, you see the flash of a blue tail like the woman had when she was a mermaid. Apparently she didn't lie about how the pool works. Now to escape while you can!
You struggle toward the steps leading out of the pool, but are struck from behind. Your head is held underwater until you're desperate for breath. You are released enough to get your head out of the water and gasp for air.
You struggle and turn to come face to face with the angry mermaid. She shoves you forcefully against the side of the pool and she's strong enough that even though the steps leading out are tantalizingly close by you can't escape.
"Damn you! I was almost free of this place!" she screams at you. "Do you realize what it's like to be trapped in here alone for years?"