Hmmmmm. How do you know everything?
I don't; but my google-fu isn't half bad.
I will investigate on site. How did I miss that? I have never used those stairs.
Dunno. I've rarely driven to this store (and more rarely still walked to it from wherever. But when I have driven to it, I've usually parked on the ground floor, so I'm sure I would have ignored it.
***
Here's how the google went, first I looked at the aerial pic and assesses that there were 2 structures above the second-level deck, in the s/e and n/w corners, and thought these might be stairs.
I tried to see if Google had documented the garage itself, but it has not.
Then I looked at the perimeter on streetview where I saw the structures. I found those stairs right away. On the N/W side there is an exterior door, but its unclear to me if there are stairs, if there are, its likely they are emergency exit only.
Then I googled the parkade again, but not looking for images, and I found the reservations sites for spaces.
Took me about ~3 minutes total.
Shhhh, don't tell anyone my secrets....
Edit to add, it just popped into my head that streetview from the Gardiner might allow me to see the structure at the n/w corner of the deck, et voila:
Definitely a door there, not sure about access rules.