Movie question: The Beyond 1979 - directed by Lucio Fulci, what happened to the !

Movie question: The Beyond 1979 - directed by Lucio Fulci, what happened to the couples finally?

this italian classic horror is very unique,
what happened to the couples at the end of the story ? did they enter the beyond forever and will never come back to the realworld ?
that is the unrational sense one can´t understand

All hope is lost in the end. Liza and John find themselves transported impossibly from a hospital stairway back to the hotel's basement. They enter a wasteland that the artist Schweick was seen painting at the beginning of the film. After wandering around in fog and among lifeless mummified bodies, the two go blind and fade into oblivion.