Accreditation standards that apply to all medical schools require that admission decisions be made by a committee comprised of medical school faculty members. The decision to pull someone from the waitlislt may be in the hands of the dean of admissions on the principle that the admissions committee has approved the admission pending an available seat.
The UF scandal, almost 10 years ago, IIRC, involved the Dean of the medical school, not just the Dean of Admissions, who was pressured from the University President who was pressured by the Governor who was trying to please a political bigwig whose kid was trying to get admitted outside of the usual process. Members of the adcom who had been bypassed blew the whistle, chaos ensued, the Dean resigned and eventually left the state, and the kid matriculated, and later graduated, medical school. (As an aside, things did not go well for the kid's father who underwent further scrutiny and ended up in prison for white collar crimes related to the handling of campagin donations.)