Grown up girl wets her panties

Melanie is a normal 24yo woman. A job, friends, likes to go clubbing. She nodded off one night in her bed and woke with an odd sensation. She had peed in her pyjamas. She has not wet the bed since she was three years old. Not only that, she woke not in her bedroom but in a nursery where everything is oversized to suit an adult. WTF?