I went back and to my surprise the front door of 71 was wide open. I explored most of the second floor but I stopped and didn't try the door to the first floor because there were sounds coming from there; perhaps the reason the door was open. I've uploaded some photos.
These buildings together have 3 addresses: 71, 75 and 77. There is a sign out front saying the city proposes to turn this into a 5 story student apartment with 129 bachelor units and 50 parking spaces. For now it seems this lot is used by students for free parking. Perhaps I'll go back and try to get some photos.
It looks like you were in 75 leland, 77 leland looks different inside. Where was your POE?
Nice, gives something to do in the McMaster area while waiting for 'hospital stuff'.