It establishes as the primary event.
The episode centers on several couples reaching critical turning points. After a season of "will they/won't they" and professional tension, Meredith finally gives in to her attraction to Nathan Riggs. Meanwhile, Owen and Amelia take a massive leap in their relationship, while Jo and Alex hit a definitive wall regarding their future. [S12E23] At Last
: Alex is tired of waiting for Jo to marry him. He gives her an ultimatum: marry him or they are done. Jo refuses to give him a straight answer, leading to a devastating breakup. It is hinted that Jo has a deep secret preventing her from saying "yes." It establishes as the primary event
This episode directly sets up the :
Her refusal to marry Alex sets the stage for the reveal of her "Paul Stadler" backstory. Meanwhile, Owen and Amelia take a massive leap
It creates a dynamic, as Maggie reveals to Meredith that she also has feelings for Riggs, unaware that Meredith just hooked up with him.