Excellent picture. This last one shows quite a bit of detail. Lower right of frame you can see a completed stairway leading up to the promenade level sandwiched between two escalator pits. You can also see completed cladding on a few rows of columns. And if you look carefully at the ceiling you can see completed ceilings over the stairs/escalators. (Edit. It also looks like the terazzo floor is already done within the area surrounded by red tape.)
The concentration of completed elements along this specific line lead me to believe a new pedestrian corridor will open along this route fairly soon. It would be linking the promenade to the TTC moat while construction and fit-out work progresses on the leather shop bypass area and the new Bay concourse proper.
If I had to wager, I would hedge that this “new bypass” corridor opens to handle the main GO-to-TTC traffic before the alternative primary connection opens on the lower retail level (linking Bay, Union Square, and York food court).
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