I just noticed today that the eastern half of the "temporary ramps" in the entrance structure at the south Telus/MLS doors (think of the narrow concrete floored ramps with white walls that go up to VIA) is being demolished. It looks like the powers that be might be getting ready to shift passenger flows into the lower level retail soon enough.
Once the project is complete, passengers who enter the station from the south Telus/MLS doors will descend a flight of stairs to travel north in the new lower level retail under the VIA concourse. This wide retail corridor meets a main junction under the north end of VIA where you can go left for the escalators up to the York concourse, or right for escalators up to the Bay concourse or onward to the new corridor to the TTC, or straight ahead and up a flight of stairs that lead up to the area in between the two "exit" ramps from the VIA concourse and the retail "promenade" area under the great hall.
1) These are pictures from May 2016 showing construction progress on the new lower level (under VIA). The retail areas underneath the VIA and York concourses were roughed in sometime early 2016, and while mechanical work was still progressing the main corridors were now complete. This is looking north up the main north/south retail corridor in the new lower level, the picture was taken from the bottom of the stairs leading up to Telus/Maple Leaf Square.
2) From the same vantage point as the above but looking south this time you can see the new flight of stairs going up to the same grade as the Telus/MLS lobby. If you look closely in the background you can make out a red steel beam running over a plywood door, this red steel beam is part of the support structure for the temporary ramps that currently go up to the VIA level from Telus/MLS. The Telus/MLS lobby hallway concrete "box structure" and floor slabs were poured at the correct grade and are ready to be connected through to these stairs and the new retail.
3) Looking south through the plywood door in the above picture. This is underside of the floor slab for the "temporary" ramp from the Telus/MLS lobby leading up to the VIA concourse level. This is the lower ramp segment below the T intersection.
4) This is looking north from the main intersection of the east/west and north/south corridors in the new lower level retail. You can see the rebar which was ready for the stairs to be poured which will take passengers up to the retail area under the great hall. Effectively once done you will be able to enter the station at the Telus/MLS doors and be able to basically walk straight ahead (albeit with a few grade changes via stairs) right out to Front Street. Given that this picture dates back to May 2016 and the recent (early 2018) construction activity around the VIA exit ramps area I am willing to bet these stairs have since been poured and a new wall opening made on the promenade level between the VIA exit ramps. This would mean multiple entrances ready and that both the main north south corridor and the western half of the new lower retail could be ready to open some time before the Bay concourse.
5) The "You Are Here" key. Picture locations marked with red arrows.