While Daphne practiced, Stephen wandered over to his bookcase, his eyes skimming the spines. He was still partially paying attention to his student. He just didn't want to make her feel like he was crowding her or be an overbearing teacher. She needed to be able to concentrate; something that was really difficult to do while someone was staring you down.
He'd fish out a book or two, tucking them under his arm. There were chapters on temperature regulating spells in both, though Stephen would encourage Daphne to flip through other sections as well, if she wished. Just as Wong had told Stephen himself: there was no such thing as forbidden knowledge, only forbidden practices. And as far as forbidden practices went, Daphne certainly could not accidentally summon Dormammu with the books she was being given.
It wasn't until he noticed a snowflake or two drifting through the air did Stephen turn back to Daphne. Oh, on a positive note, it looked like she's nailed that spell. However, ice was starting to coat the cement floor, so maybe she was overachieving a little bit.. "Ah, careful, Daphne. Don't freeze yourself.."