Yeah. I can't believe 100 million years would let you survive as a person. You'd break a few months after entering that room. Have there been any entertaining devices? No? You'd break. Yes? Even then, you'd break. It's 100 million years!
And there is only so much stuff you can learn in that kind of isolation on your own. You'd also need input and a reminder, what is considered normal or else, I imagine, you'd end up developing a kind of sword fighting style, that might leave you open for any kind of attacks, because they stopped to make sense somewhere and you'd expect other attacks, nobody ever thought off. Also fighting yourself would be a great training method, as you'd be able to more easily spot mistakes in your stance, I'd expect. But then again you are still on your own and wouldn't learn stuff from the outside.
Except from learning the shadow self-fighting technique, 1000 year should have been enough for his training. Actually both: To train AND to lose his mind.
Or maybe some kind of mind stabilizing/repairing/regenerating effect preserved him, as his body also didn't age.
Also: Does he really need that school anymore? Settingwise, there shouldn't be anything left for him to learn....hmmmwell,...Okay, 3 year, in comparison to that room, aren't that much and he'll gain a title for his job hunt...though I'm not sure he'll need a title with his fighting abilities.