I'm sorry to hear about your predicament.
I have to agree that you would need to excel on the interview in order to be considered for any roles within the MBB firms. Culture fit is indeed one of the more tricker aspect of the case interview. However, it is a crucial element of management consultant recruitment.
As a client facing role, a consultant needs to make sure they are acting in accordance to the client's preferred culture, else the firm is risking their reputation. Merely solving the case and completing the project is one half of the equation, managing the relationship is the other.
Typically, MBB firms are background-agnostic. Especially if you are an undergraduate or recent fresh graduates, as long as the prospective candidates displayed strong performance in the case interviews and showcase cultural fit with the firm (passing the "airport test"). Hence, I would presume it is either the case performance or culture fit which was the key reason that underlies the final decision.
With regards to applying for internship, there are 2 types of internship. The structured summer internship program as well as the unstructured project-based internships.
- For the first one, it might be challenging to request for consideration to be included within the program, given that they would cross-reference your previous performance. Even if HR is willing to consider, you will likely need to go for another round of interviews.
- The second one is generally more flexible than the first one. I know some people who have been rejected on full-time basis that underwent project-based internship. Later on, they leveraged their experiences and managed to get a full-time offer. Mind that not every office / region offered this type of internships.
In summary, I would suggest trying to inquire about the second internship type to the HR as well as see if there are other offices that might be more suitable to your communication style / culture. It would work best to rethink of why are you particularly interested in this particular office, which as you said is located on a different region, with different cuture than what you are used to.
Feel free to DM me if you wish to discuss further on the matter.
Hope it helps and all the best for your last 1 year in university.