Stacy McKee, the head writer on "Invest in Love," shared some thoughts on last week's terrific episode of Grey's Anatomy on the show's official writers' blog.

Below are excerpts from Stacy's column, with a link at the bottom to her full entry ...

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We’ve been planning an all PEDS episode for some time. Arizona is a regular now and we have started seeing more and more of her – but for the most part, we always see her helping Callie through crisis after crisis. We haven’t yet really given Arizona a crisis of her own.

So what better chance than in an episode where every patient is – in essence – her patient. Every patient is from the PEDS floor. PEDS, where things work a little bit differently, where the patients believe in magic. Because they are kids. Sick, dying KIDS.

To balance out all the sadness in the episode, I knew I had to incorporate a story that would make me (and you) feel good, too. Enter Alex. Saving a teeny tiny baby. In the NICU. Shirtless.

See? A happy miracle baby story! And a half naked handsome man! 

Derek gets some encouragement from his doctor, Lexie Grey.

Mark Sloan is right when he says that surprise parties are hostile. Because they ARE! One of my favorite unscripted moments in the episode comes from Cristina when she’s eating breakfast and listening to Mark’s take on surprise parties. She TOTALLY sides with Mark.

And, if you were paying attention, you may have noticed that the surprise party moment is the ONLY moment in the entire episode where Arizona cries. Even though, as we’ve established, Arizona tends to cry in the face of authority figures.

Arizona is a people pleaser, which is why she winds up agreeing to a surgery she doesn’t believe in, she’s trying to please Richard. He’s the chief. She doesn’t want to let him down.

But even after standing up to him, after kicking him out of her OR, she still doesn’t break down and cry. After losing Wallace, Arizona still doesn’t cry. After having to face the Chief and face Jennings in the wake of losing Wallace, Arizona still doesn’t cry.

And finally – one of my favorite moments in the entire episode comes in the very last scene – from Callie. For those of you who have been watching Grey’s Anatomy for a while, you know that Callie tends to blurt things like “I love you” out – often prematurely.

If you recall, she did it with George, and he never could say it back. She’s a gal who jumps in head first, sometimes blindly, and we’ve seen it bite her in the ass.

So what I love love love is the moment when, after the horrible day that Arizona’s had, after the disastrous party, after losing one of her favorite patients – Arizona comes home, takes one look at Callie in her lingerie and that silly party hat – and Arizona says “I love you” first.

The look on Callie’s face when she hears that? Oh man, I’m starting to tear up again. It’s just so unbelievably vulnerable and sweet and lovely. Okay. Totally crying again.

Follow the link for the entirety of Stacy's blog ...

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.