re: Slab:
If you look closely at the video posted in the Michael McGrath interview:
http://urbantoronto.ca/news/2011/07...-bloor-construction-technology-groundbreaking
You will notice that there is a short, 1s building raised between say, the beginning of the clip to the 0:08 mark. It will be incorporated to the podium later on - and I think it must be vehicular access point or whatever. That's what the slab is for. Wish I have a site plan to confirm.
AoD
I know it will be part of the complex, but based on the width of the slab, too small for truck delivery. Its thick enough to support them.
Time will tell us what this area will be use for unless someone can get hold of the construction drawings that will state what it will be used for.
As it stands now, there is 2 exit from the subway with one exit in the Bay and one in the current building. Once you reach street level, you have currently 3 exit with one to Bloor St, one to the south and one to Yonge. When excavation starts, you will only have 2 street level from the current building. Getting 1,000-3,000 riders off those platform will not be easy.
If something happen at the Yonge & Bloor station, it will be mayham trying to get people off the platforms today. The Bloor line has an west exit to the street, but small.
By right, TTC should had talked to One Bloor about adding a number of exit to it even as fire scape exit.
TTC should have looked at building a south platform for the Bloor line with exit into On Bloor to either get to street level or the Yonge line.