Dawn of a new era. What brought Derek to Seattle in the beginning has finally come true. He's Chief of Surgery. Okay interim, but still Chief. Of course his relationship with Richard could very well be beyond fixing as a result of his ambition. But he's convinced himself he was acting in the best interests of the hospital (you could argue this is true) and his becoming Chief was just a happy result.
Meredith has come so far. A few years ago, when things get hard and she gets mad, she would have left. But now she stays and works through it with Derek.
Alex is also leaps and bounds from where he started out. Remember when he freaked on the elevator and George had to perform an emergency procedure on a patient? Tonight he didn't hesitate. Not only that, he stood up to a patient without getting physical. He's been destined for peds since almost the beginning. Addison thought so. Bailey thinks so. And now so does Arizona.
Owen was definitely trying to use sex to ignore their problem. Except it only worked for so long.
I've said it before and I'll say it again. Lexie and Mark BROKE UP. Yes. He is allowed to be hurt that she slept with Alex. Just like Lexie is allowed to be hurt that he had sex with Addison. But you lost the right to act superior over the other because he/she slept with someone else when the relationship ended.
Hilarious that Cristina burned her ass on a vent. Reminds me of graduate school when one of my roommates was so drunk she burned her ass on the radiator pipe in the bathroom. I was the only one willing to bandage it for her. True story.