213,000 square feet seems like a relatively small square footage for 3 storeys, given that the original 10-storey store was reportedly 1,000,000 sq. ft.
Having said all that, I am terrible at math, and my memory of the store is hazy (given I stopped going once it became Sears), so please let me know if my numbers are off.
Some of the space at the far northwest corner might be kept for the elevators and reception for Sears' offices on the upper floors. Still, 213,000 sq. ft. is a big store, about 50,000 more square feet than a typical Walmart Supercentre.
The numbering of the floors is slightly confusing as Eaton Centre and Eaton's/Sears used different orders.
In the Eaton Centre,
Level 0 is the food court (former Eaton's floor 3B)
Level 1 is the corridor where Old Navy is and the dead corridor to Canadian Tire/Mark's, continues south to Richtree and Queen Station/Bay. This was former Eaton's floor 2B, taken over post 1997 bankrupcy.
Level 2 of the Eaton Centre is the lowest level of Sears - men's clothing and such (Eaton's/Sears floor 1B). This continues to street level at Queen Street to the south and the southbound trains entrance to Dundas Station to the north.
Level 3 is the old Eaton's Main Floor (now Jays shop, shoes, luggage, cosmetics, etc), street level at Dundas Street, Apple Store/Bay bridge on south end.
Eaton's/Sears floors continue with 2, 3, 4, 5.
There is a Level 4 in the Eaton Centre, equivalent to Level 2 of the store, but it is used only for Mr. Greenjeans, Lenscrafters, 2nd floor entrance to Indigo and access to elevators for parking and offices.
Sears offices are the former Eaton's floors 6, 7, they'd be equivalent to the Eaton Centre's Levels 8 and 9 if they existed.
What is Sears/Cadillac Fairview going to do with Levels 4 and 5 of the store? Did nobody want them?