Is it ok if my 5th choice is at the same uni as one of my four medicine applications?
Yeah, unis are well used to this
It may be worth emailing them to see if they'll accept a personal statement specifically for the 5th choice course, (assuming it's one you would actually want to take up if med falls though).
Yh I have the same question because I've heard that unis will prefer to give the 5th choice rather than medicine as you're still applying to their university - but I'm not sure if this is true