Who came to Montag's door? What does this imply?

Beatty comes to the door. He's there to check on Montag.

"Captain Beatty."
Montag did not move, but stood looking into the cold whiteness of the wall immediately before him.
"Go let him in, will you? Tell him I'm sick."
"Tell him yourself!" She ran a few steps this way, a few steps that, and stopped, eyes wide, when the front door speaker called her name, softly, softly, Mrs. Montag, Mrs. Montag, someone here, someone here, Mrs. Montag, Mrs. Montag, someone's here. Fading.