"I see, just as you'd expect from an extreme sadist."
This is just as you said, the sadist is Evangeline.
"Coming so far with just a container."
I think he's talking about magic power of Negi. Evangeline explained that people have "magic containers" inside them, and just with that, Negi reached that level already. Or maybe, he's talking about Eva's village.
"What a repulsive way to be brought up..."
I think that Rakan don't think that these methods are the right to make a level up, that's why it's repulsive (hellish).
And since you don't know japanese (me either), why you just don't ask in AQS forums? This is the thread with the discussion:
Oh yeah, I saw F-H translation and I didn't undertanded NOTHING. WTF is "Do S"?