Thanks for the info. Most likely they're cutting off utilities, since they dug the hole in front of a section of the building that hasn't been used in years (it was once a cafe). We'll see if they cut off the other sections when the owners move out. There are no possibilities for expanding the lot, although there are some development opportunities across the street.
I did find one example of infill on a small lot in Centretown, at 246 Gilmour
. Something like that would be nice. Hope they don't land bank it for ages.