While completing academic work is needed to retain any acceptance, a more important concern would be maintaining superior academic work if you are one of the 60% who do not get in and become part of the 25% per cycle who have previously applied to medical school. Lets go thru these two scenarios
When you apply to any medical school you have agreed to adhere to all policies and requirements for applicants as they are detailed in student handbook, policy listed on website, submitted in any application, or noted in acceptance or matriculation agreement. Usually, this will include a phrase along the lines of "acceptee must successfully complete current academic work." That would usually mean a grade of C or better in all coursework and being awarded your degree if noted previously on your application. Now, if the med school has prereqs that require C+ or higher, they could reasonably say all coursework must be C+ or higher. Obviously, if you have outstanding prereqs, they must be complete according to the med school's requirements. All this requires formal evidence as in final transcripts and degree. So if you had to take a summer class that finishes a week before med school orientation but final transcript doesnt get there in time, you may be into a forced deferral. This is because schools get accredited in part on setting policies and adhering to them. If they frequently waive these requirements, they could get dinged in LCME re-accreditation audits.
Reapplication is the more important issue and the issue should be obvious. If you apply to medical school, go on several interviews that interfere with your class schedule, causing you to do poorly in the term, you then would be a reapplicant with lower than typical grades. Not a good position to be in.