Actually, in terms of seating capacity, Ryerson is planning to do exactly as you guessed. Scroll to the bottom of this link:
http://www.ryersonrams.ca/ViewArticle.dbml?DB_LANG=C&DB_OEM_ID=22300&ATCLID=205584532
"The new 1,000 seat Coca-Cola Court will serve as the primary home court for Ryerson's basketball and volleyball teams. The Rams will also play select contests in the Mattamy Home Ice arena."
I've been told they already purchased a separate floor that was used during this past year's NCAA final four, and that the plan is to convert the rink for "big" games, such as playoffs, the annual frosh week game, maybe also against U of T, etc. I've heard that would boost the 2,600-seat rink to about 4,000 compared to the 1000-seat capacity in the gym.
I would expect this also to happen for the Pan Am Games, because the Gardens is actually one of the venues and will be used for basketball:
http://www.theglobeandmail.com/news/toronto/torontos-pan-am-games-venues/article4108252/