Heres the basic run down as i see it ( i am no means correct, just a med hopeful.. probably not going to make it anyway but...).
So basically,
*First of all they look at your umat score... if its to low they chuck you in the bin and your out (I'm fairly sure there's some cut off).
*Second, They consider how well you did in the interview, because face it as a doctor you need to have at least half decent communication skills. (Im not 100 on this but if the umat is higher then average theres a tiny bit of leniency for your interview to be slightly lower and vice versa). So if your interview is crap, you're chucked out again. If it isnt your kept in the pile.
*Lastly, if they still need to cull the numbers they look at the enter. I've talked to people who are in med, the lowest enter one of them has heard of is 88 and he was a rural student so he gets some slack. I'd say bare bare minimum with fantastic everything else you'd need like 92-94 maybe if your doing some kind of bonded place...probably higher for regular. (Again leniency with a higher umat/ interview)
There are far more applicants than places, because the demand is so huge this is why everything needs to be so high.
Each stage in the process is basically looking for a way to cull more of the applicants untill they get down to a suitable number.
Also note the umat results and interview take place before the release of the enter ive heard.
So they dont look at your enter off the bat, the umat and interview comes first.
I reckon the umat is really the clincher cause it decided wether you even get to have an interview...