During my interview they said that everyone gets a score. Above a certain number, admit immediately. Under a certain number, reject immediately. The rest are hold. The line for "admit" lowers as the cycle progresses and they have a better idea of the spread of applicants.
100 points total possible:
20% = defined by a combination of MCAT and GPA (don't know specifically how this works out but I'm guessing it's a
LizzyM type combo)
30% = MMI ratings
50% = your 1-1 interview & essays/rest of your app.
So MCAT and GPA will end up factoring into the total decision since it's your total score of these three that determines the outcome.