"Let me guess," Mark smirked, coming up to the nurse's station behind Derek. "You and Meredith are back together and you've been up all night doing the horizontal salsa."
"Mambo," Derek corrected, not looking up from his chart. "Horizontal mambo. Meredith and I, we're just friends."
"Sexy friends," Mark grinned.
"You're like the worst, most juvenile human being I've ever met in my life," Derek told him, finally making eye contact.
"You know the first step to recovery is admitting you've got a problem?" Mark suggested.
"How many nurses have you slept with this week?" Derek fired back as he walked away.
"That's not a problem, man. That's an adventure!" Mark called after him.