Episode 5.17 - I Will Follow Du Into The Dark - Sneak Peeks 

Okay so I don't like Mark and his big attitude, Derek has every right to be sad and angry (he got called a murderer for Christ's sake!). Mark's the one who picked the wrong time and place to update on his manwhore activities, so yeah, he deserved to be punched. and it's not like Derek always get all depressed over every single patient he lost...jeez, insensitive much!

LOL and I love Cristina~