How does Buffy end up naked?

Buffy takes the red pill

Buffy was having the dream again. The dream in which she was trapped within a steel cage and being taunted by vampires. She was naked in this dream; indeed, she was naked in a lot of her dreams but in this one, she felt especially exposed.

Then she heard a growling sound behind and Buffy's dream self realized that someone else was in the cage with her.

"Oz?" she wondered.

Then she looked into the eyes of the hairy beast behind her and realized that it was not Oz. In fact, it was not anyone Buffy recognized. And it seemed fairly obvious from the way the beast kept growling at her that it in turn did not recognize her.

Then she woke up. She expected to find herself safe at home in her bedroom, dressed in her favorite nightgown. Instead she was covered by nothing but a sheet and secured to the rails of a unfamiliar hospital bed by leather limb restraints. Restraints that did not yield to her usual Slayer strength.

"Okay," she said. "This is new."