I noticed my D: drive was marked as dirty and some folders were coming up as corrupted, so I recovered as much data as possible, and then scheduled a chkdsk /r /f on next restart, and I've been here since Thursday (it progressed a bit throughout Wednesday):
I now need to urgently access files on my C: drive, but don't know if I should interrupt this process with a forced power off.
Well unfortunately if it's the bearings dying, it continuing to run will likely overheat it and you risk locking it entirely. I've had to freeze a drive before scanning it and backing up, but it's only about 50% successful.
Yeah, that would be another theoretical possibility OP will need to weigh.