I don’t think Shearer was ready to quit just yet. Her last two pictures did not do well and they were her own bad choices (as she said in response to rumors that Mayer sabotaged her, “on those last two, nobody but me was trying to do me in” – from memory). She might well have retired by 1945 but I doubt she wanted to go out on that note. Garbo was always a little phobic and the longer she was away the harder it became to come back, and as time passed she was indeed worried about how she would look. As we now know from the tests that have surfaced from the movie of La Duchesse de Langeais that never happened, she had nothing to fret about.
That was a fine sequence and it did feel true to life.