I watched the 7Sage video for this particular game but fail to understand a particular rule.

The rule was O1-R1-R2, which made O only possible on wednesday OR thursday. However, why isn't O1-O2-R1-R2 possible, that is, having O on both wednesday and thursday before R1 and R2?

http://classic.7sage.com/lsat_explanations/lsat-57-section-1-game-2/