Here's what hopefully is the last update on the map. It fixes the jank of the canvas puzzle, fixes the aforementioned building demolition that wasn't working, fixes leftover fullbright visibility in some vents, and also now the broken automatic shooters seem to work although I barely remember touching them. So it should play completely as intended now. Sorry for a half baked, buggy release (and mess of posts), this was a very spontaneous map that happened in a burst and although I did test it a lot whilst making it, by the end of the process I was exhausted and couldn't keep up with all the possibilities, but now should be fine. Thank you for your patience.
EDIT - upon further testing the shooters weren't completely fixed, but I found out what was causing them to act loose (presence of a MASTERSWITCH with matching channel somewhere else in the map), now they are fixed for good. Also fixed more loose textures.