Tonight's Grey's Anatomy was all about Derek, and finding your peace.

However you can do it, that's how you do it.

Derek narrates the episode and opens by talking about what drew him to surgery: the quiet, the shutting out of everything else in the world.

He's studying some scans when Isaac, a lab tech, come in and shows him an amazing MRI of a giant, very dangerous tumor on his spine. Isaac's the patient, and he talks Derek into taking on his surgery.

It's regarded as impossible but McDreamy thinks he can do it.

One by one, Cristina, Mark, Callie, Lexie, Hunt, and Arizona all come in and offer support while Derek's trying to figure out whether to take the case.

Even Bailey's blown away, calling the tumor dangerous, complicated, smart and beautiful - the reason she got into medicine. But the Chief won't go near it - it's just too dangerous, and too expensive.

After all, they might need to cut the spinal cord to get it all out.

Even after Derek tells him that the patient is an employee, the Chief says the hospital's not a charity, and they don't have the pro bono budget to cover higher surgeries for every employee.

They butt heads. In the end, Derek defies the chief and his new computer generated schedule and books Isaac for surgery. He's gone rogue.

First, a contest among the residents will determine see who's got the skills to handle microsurgery, and Jackson Avery gets to scrub in after Cristina blows it. So does Lexie, who'll keep an eye on Derek.

Avery brags about how he never has to take breaks and that Lexie is just a bitch. So Lexie decides to wear a diaper so she can stay in surgery for longer than Jackson. Cristina finds out and is impressed.

Before he goes under, Isaac tells Derek that he needs to be inspired in this surgery - and if need be, he should cut the spinal cord. He says he's survived war and tragedy, and he can do without his legs if needed.

It doesn't go well.

Derek gets in there and finds that the tumor is much more involved than it looked on the scan. He stands there for 10 hours trying to come up with a plan to attack the thing, before the Chief comes in and boots him out.

He later explains to Isaac that it was too risky, and since he still has use of his legs he couldn't bear to cut the cord.

He'll do better tomorrow, Isaac tells him. Derek is dumbfounded.

Derek goes home and talks it through with Meredith and comes up with a new strategy. He's gone all zen, an knows he needs to just go in and cut.

The next day, Derek cajoles Richard into allowing him to the surgery, but just to cut the cord, which should only take an hour. Of course, he has absolutely no intention of doing that.

He's going all in, and will be there 26 hours if needed. Of course, that is physically demanding, and a tense, dehydrated Derek throws up in the middle of it.

The real trick is when he's down to the last set of blood vessels that connects the tumor to the spine, and he has to pick the one to cut.

The wrong decision could kill or paralyze Isaac.

In the end, he makes the right call. Derek not only saves Isaac, but also doesn't paralyze him. When he wakes, Isaac's convinced that the surgery didn't go well, because he can move his feet.

But when he learns what really happened, it's with such relief and joy.

Just the same, Derek runs into the chief, who all of the attendings have blocked from his OR during Isaac's surgery.

We can't keep fighting, Derek tells him. Let's try to put this behind us and move on. And then the Chief fires him. Right. Derek adopts a little bit of Isaac's Zen by telling the chief to sleep on it, and they'll talk tomorrow.

He walks away. Awesome.