The scene with Jaime and Cersei was a long time coming. Now that Cersei has her heir and what she believes to be her hold on power, nothing else matters to her--not even Jaime. It took him this long to see how far gone she was, and crushing to him that Olenna was right about her assessment. Cersei's power is all that matters to her, and now looking back you wonder if her fierce love of her children was only ever due to sustaining that power as mother/Queen Regent.
Also, I figured Baelish was going to be the one to die this episode. Sansa has always been steadfast in her distrust of him, and for her to flip so easily would've been way out of character. Ironically, Baelish is a master reader of people but he was so blinded by her ostensibly falling in line with his plan that he didn't see the irony of the lessons he doled out this season.