First, you have already answered your question yourself. Who told you this will impact negatively? I suggest you stop being negative. The first thing you have to do is have faith in yourself and be confident about your actions. You have a valid reason, which I believe is really good, and no recruiter can deny accepting this reason for your gap. However, they will certainly try to judge your confidence in your decision, your life's goals, and your focus, which actually matters to all.
I agree with Mr. Samvedan and all the other people here.
Secondly, until you experience an interview, how can you say that this will affect you negatively, even though you know that your decision to pursue MBBS aligns with your career progression and that you took the right step at the right time? The simple answer to your question is that you need to explain that you were preparing for MBBS as part of your career plan and then confidently define your current career plan without hesitation. Your confident response is crucial here.
Best of luck.