Enligt Disney Wiki kan Allen överleva under vatten så länge som Madison är med honom:
When she reveals that Allen can survive under water as long as he is with her, Allen realizes she was the young mermaid he had met so long before, and although she warns him that if he comes to live in the sea "(he) can't go back," he jumps into the water after her and they elude their pursuers. Together they swim along the ocean floor toward what appears to be an underwater kingdom.