Could leave lasting creases in delicate stuff.

Sounds like they've never tried fixing an old camera before lol. It's usually a full tear-down, not some quick tweak. People just don't get how fiddly that stuff is. Maybe just hand it back and say it needs a pro.

Wow, you didn't crack ANY plaster? In an old brick building? That's the real miracle here. That old plaster is like working with solid dust, it cracks if you look at it wrong. I usually end up with a dozen hairline fractures just thinking about running a cable. The signal problem feels like a smaller issue compared to that.