"When you stand in the OR, your patient open on the table, all the world's noise, all the worry that it brings, disappears. A calm settles over you, time passing without thought. For that moment, you feel completely at peace." A lab tech named Isaac, who we have never met but who seems well-loved, comes in to show Derek some scans. They are of a monster spinal tumor, and while Derek has seen this type before he's never seen one this big -- it's worked its way up the spinal cord and taken over the blood supply. Derek is surprised to learn that the patient is still walking considering that he should very likely be paralyzed or even dead with this tumor. Isaac asks if he'd have to operate quickly and Derek tells him that while he'd love to operate on it, he'd have to cut the spinal cord to kill the tumor. He then asks Isaac who the doctor is and is stunned when Isaac tells him, "You," with a lot of dramatic drum music to back him up. Isaac admits that these are his own scans, and he wants Derek to take it out. There's a lingering shot of the giant spidery tumor on the scan that stays on the screen while everything else fades to white for the title card. They're getting fancy this season!
Isaac explains about the various wrong diagnoses he got from different doctors, and how when the pain finally started to affect his work, he did an MRI on himself. Derek tries to tell him that he never would have been so candid if he knew, but Isaac cuts him off and plows ahead. What he liked is that Derek was inspired rather than defeated by the tumor. Isaac then admits that he researched all of the neurosurgeons in the country to find one that was both the best and who took risks. Derek fit the bill, so he got the job at Seattle Grace. He's very lucky that all worked out for him given that the hospital has no money and just laid off half its workforce, but I already really like Isaac so I'll ignore all those niggling details. Derek tells him that he can't do the surgery, as it would kill Isaac, but Isaac just tells him to think it over, and to "Think yes!" During this whole talk Derek had been getting and ignoring pages, which turn out to have been from Cristina, who storms in because he's late for a procedure. She sees the scan of the tumor, however, and excitedly declares, "Screw the shunt, let's operate on THAT."