On last night’s long-awaited episode of Grey's Anatomy (Season 8, Episode 18: “The Lion Sleeps Tonight”), we finally got to see how Cristina (Sandra Oh) was taking the news that Owen (Kevin McKidd) cheated on her during their prolonged disagreement about the abortion and their future.

Other than our observation that Sandra deserves an Emmy for her performance this season, we were moved, once again, by the friendship between Meredith (Ellen Pompeo) and Cristina. They are truly each other’s “person,” and they understand each other better than sisters.

So when Owen accidentally told Meredith that he’d cheated on Cristina — twisting the knife a bit by yelling, “It was just sex!” — she was furious that he’d told her something Cristina clearly didn’t want her to know yet. As Mer pointed out, Cristina not telling her meant that she was still considering forgiveness.

In one of the final scenes, however, Meredith had a ripe opportunity to tell a clearly hurting Cristina that she knew, and that they could talk about it. Instead, she sat by resiliently honoring her friend’s decision not to fill her in.

What do you think: Should Mer tell Cristina that she knows, and offer her opinion? Or should she continue to play by Cristina’s rules and wait in silence until she brings it up?

Grey’s Anatomy returns with an all-new episode on Thursday, April 12 at 9 p.m. ET/PT on ABC.

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