As I understand the chart Pennsylvania Duck posted. we can lose to OSU and still be in if UCLA beats Cal. The only way we are not in, even with a loss, is if UW beats WSU *and* Cal beats UCLA. The key would be our beating the highest common opponent (i.e., UCLA) with UW. If Cal beats UCLA (and we lose to OSU), then OSU becomes the highest common opponent.
Even though UW beat us, in this scenario it would be a three-way tie for 2nd with UO, UW, and Utah. Head to head is not factored in because UW did not play Utah. Utah also lost to UCLA.
No one wants to back in, but it would be better to make the championship game than not.