Mark's goof was not being up to bar with Melissa. Even though he proved he could maybe be an effective assistant, he has also proven that he sometimes will be ruthless to do things and not as honest as he should be.
Andy Dick: "I don't want tap water from L.A...from the bowels of L.A.!"
Andy Dick: "...And I dreamed that I was a giant chocolate eclair, and I didn't know what the f*ck it meant."
Andy Dick: "I know you won, but you're still my b*tch!"
Melissa is Season 1's Assistant! Congratulations!
Mark is the thirteenth assistant to get eliminated.