Bugger. My Mac Pro's kernel panics got worse, to the point where it won't even boot. Running Disk Utility in (Internet-downloaded) Recovery Mode shows that the SSD doesn't even appear in the list of attached storage devices. So, to prove that it's the SSD and not something wrong with the Mac Pro, I swapped the SSDs between my Mac Pro and my rMBP (Apple-branded, 1TB). Voila, the problem is the EVO 960 - the rMBP exhibits the same issues with that SSD installed.
The rMBP started first time and I was able to run Recovery Mode (from the SSD, not the Internet) -> Disk Utility and verify that the SSD was present - I even ran First Aid on it. But after hitting Restart, it died shortly after loading the desktop and whilst loading startup apps, etc - heavy load for a boot drive.
Using a thermocouple to measure the temperature of the flash chips on the front-side (label-side) of the SSD, I can see that the chip nearest at the board-connector end gets way hotter than the others - it climbs to a max of 56 ºC (132-133 ºF) whereas the other chips stay at around 30-ish ºC. That max temp remains even after the rMBP has crashed (flashing folder "?" icon on screen), i.e. with no load on the SSD.
The EVO 960 is undoubtedly kaput, and it appears to be temperature-related - 'proven' through the fact that Recovery Mode loads off the SSD (not the Internet) and First Aid can be run on it - but 30-60 sec of boot-up and desktop load-up is too much for it. So my working theory is that the SSD has a temperature-related fault.
The SSD is still under warranty, but as FileVault is not enabled, there's no way I'm gonna send it back to Samsung for warranty replacement - not unless I can find a way of erasing it. I'm thinking that it might be worth buying a heatsink and seeing if I can keep the SSD cool enough for long enough to wipe the SSD. Bit of a long-shot, but at least it would allow me to ship the SSD back to Samsung for replacement without risking my security. If I erase the SSD via Recovery Mode then that'll eliminate the boot-up temperature-ramp that's crashing it out.