He's going.
She hesitates for a moment ere putting her hand on his arm, faltering before she can find words, meaningless ones about him being one of them and how he can't leave. He responds that he's already left, bitterness sardonically tingeing every word. He grips Marna's hand just a little bit tighter and they leave.
She can feel the tears prick at her eyes, scalding needles she's never felt.
Perhaps all she's said is true, but that's not why she wants to stop his retreat.
No, it's because she can't bear to see him go off with another woman.