Regardless if she's intending on becoming a veterinarian if she's willing to commit to taking on the work (i.e., school as many have commented) she should take it seriously. From the first episode she has been struggling with her acceptance and her role as a student (to some degree) we can all sympathize with her because we've all been students and had our bad/off days.
She should know better. With regard to her image I, like many of you, would like to think it's all a ploy by the producers to help ratings, etc. but do you think Nicole would jeopardize her image without thinking about the possible outcomes not only for herself but for the other members of the group? We're not entirely sure she was drinking as neither the report nor the episode clearly show definitive proof of such behavior it for now is only speculative.
As I have not yet watched the fourth episode is there a preview of episode five? Does such behavior continue from episode four or does it show her buckling down on her school work or is it a combination of the two?