Yes, but not much is user serviceable these days in Apple products. Macbook Pros have a iFixit repair score of 1; you basically can't get worse than that (maybe the dial goes to zero, I'm not sure, but even so, 1 is still friggin' rock bottom.) You might as well never hear what the problem actually is; if the machine can't complete Apple diagnostics they'll just trash* the logic board most likely and that'll be it.
*Well, recycle. Because we're environmental these days, luckily.
Possibly. Computers could glitch randomly for any number of reasons. A cosmic ray might've hit your CPU, causing it to crash. Who can say. If it starts happening repeatedly, worry. At least unless you don't have applecare.