Interviewing while working on the Street is gonna be really hard for a number of reasons:
1) Your bosses will know what's up. Why? Because no one takes vacation time their first year, especially in their first 4 months of work (which you'll have to do). If u say ur interviewing for med school, they will probably make life pretty hard for u since they'll have "wasted" all this energy training an analyst who will leave them in a year. You will likely face a hostile work environment for the rest of your time at that company.
2) Analyst programs at all BB banks are 2 years long. Many interviewers at med schools know this. If you apply in ur first year with the intent to matriculate your second year, interviewers will know you're breaking your contract, and they'll question your integrity.
Good luck though, I'm sure it has been done though. And P.S. - do NOT ask about vacation and benefits in your interview. You will seem soft and uncommitted. Wait until your offer.