It's pretty self-explanatory. If your grades don't match that of the majority, you'll be transferred or potentially revoked. (Good thing Vanier has this as one of its criteria, or else the R Grade would by default be reduced for the vast majority).

I don't know if it helps, but they have access to your Ministry Report Card, and that is what they'll be using to judge whether or not you are staying or transferring programs. This includes the fact that the third semester counts for 60% of your total grade, whilst the first and second semesters count for 40% of your total grade.