I am not understanding the issue. Can you elaborate? Do you mean that it is never stated that the protagonist stops fantasizing and the description is now about reality?
I don't think it is stated explicitly, no. To me, the fact that at the end of the previous scene it said
As your imaginary landlady yadda yadda yadda...THE BELL RINGS!
"Coming!" she yells, and you couldn't agree more on those words.
Was enough of an indication that the fantasy got stopped by the actual ringing of the bell.