Graves contemplates him, assessing. Does he legitimately expect Graves to lay out every part of his plan for him? That's not how it works -- not in, well, just about any kind of organization worth its salt. The distrust is mutual, but even more important is his acute awareness that they're not in his territory, where inconvenient questions and similarly inconvenient people can be wiped clean with a whisper of a word, a flick of a wand.

That the young man doesn't want to see Credence hurt alleviates the mistrust somewhat (after all, that desire to see Credence safe doesn't extend to the rest of his compatriots, and Graves is very aware of how these things can go), and he chooses his words with care.

"An Obscurus is created when magic is repressed through fear, pain and hate." He reiterates, explains. "That twists the magic, turns it inwards, like a disease. There is a theory," His, but he doesn't mention it. "that if he can be taught to accept and access his magic without shame or terror, there is nothing for that energy to feed on. A recalibration of that existing energy should bind it to his will, not the other way around. His lessons will resume when he returns. Another alternative is the extraction of that energy from him via magical methods."