Plenty of stuff to do

The sanctum was becoming something of a second home for Theo. He had expanded from only coming to visit for the library to other endeavors.
He had begun to do his hour of meditation there. The hollow emited an aura of something Theo would describe as sublime.
Theo had actually taken an interest in the hollow itself. Having read a little about Loci in the library, Theo began experementing with the sanctum hollow. There wasn't a perfect resemblence between hollows and loci but it was enough to promote Theo to further investigation. Most of what Theo did was just on the border of his understanding of the Prime. He worked spells that strained his abilities. He tried to shield objects with the white fire, and made attempts to compel the movement of mana. The spritual image he conjured never superceeded that laws of the Tapestry, though the weave did sometimes bend slightly. Occasionally the surface would boil, bringing the pain of Paradox. Theo always stopped at that point, both to recover from the bruises that bloomed on his body when it happened and to allow the weave to smooth over.
Being at the sanctum also allowed more interaction with his cabal mates. He wanted to get to know them better and as such they soon discovered his talent for asking questions he shouldn't (more often than not) be asking. On other occasions, they would find out he could be a great audience listening with rapt attention to even obscure trivia or what hobbies they enjoyed. Theo even gets to understanding one fifth of Armstrong's math babble, after getting three books on advanced calc and trig and reading them cover to cover. Even just casual discussion is for by Theo. He analyzes it all with the intention to learn. He had learned theories of Arcanum application, the anecdotes about strange phenomenon, and even the social structure of of other Orders from how they talked of other mages and what titles they used.