Gaps are somewhat like unfinished business, especially when referencing Equity Averages. Since all other indexes have filled these gaps, IWM likely needs to play catch up. Typically IWM leads on the way up as well as on the way down. By lagging on the recent selloff, it's an odd sign of potential strength.
I don't believe a rally is sustainable based on the intermediate term, but short term and lasting 2-4 days is certainly in the cards.