Renal, having a mixture of a-levels is a non-factor when applying for medicine. Medical schools do not make assumptions on applicants' social skills or whether or not they're 'interesting' based on their choice of a-levels.
Individuals involved in the selection process may voice opinions one way or another regarding what they want from applicants (i've spoken to a few who think maths should be mandatory for example), but the application process is systematic. As a result, a-levels are treated objectively, while subjectivity is reserved for PS and interview.