During my interview we were told by Dr. Deas that MUSC ranks in the top 10 "Most Popular Medical Schools". These rankings were based on the percentage of accepted students who went on to matriculate at that same program. I found an article that backs this up and also provides some numbers:
http://www.musc.edu/catalyst/archive/2011/co6-10medicalschool.html
Afterwards, Dr. Underwood mentioned that once interviews are complete in late Spring, a wait list is created from those applicants who are still under consideration (on hold). He went on to say that if one makes this wait list, "you have a great chance of getting in".
I'm speculating here, but given Dr. Underwood's comment, I doesn't sound like the wait list at MUSC is very extensive. Furthermore, the idea that MUSC is such a popular school among those who are accepted suggests there really isn't any need for a large wait list. While I have read that USC has a huge wait list (divided into thirds), I have no reason to believe the wait list at MUSC is the same. Good news, I suppose, for the "on hold" applicants who make the wait list in the Spring!