The word special could be interpreted in so many ways, and the others hearing this didn't really know what to make of it. So, in the end, they chose to ignore Clark's remark, apart from Rokene. This was because Rokene had been paying special attention to the words being used by instructor Clark, as he went around and checked everyone's familiars.
In his head, he was creating some type of ranking system based on the words that would have been used, and so far the best was himself. That was until Buinn got picked. And even he was struggling to interpret what the instructor meant by special. In a way it wasn't an outright compliment, that was clear because Buinn couldn't even summon his familiar. If he was to take a guess the word special in this situation was being used to describe his potential.
As Clark continued to go around, there were no better compliments given than the one to Rokene and Buinn.
