Try this:
To get into the arena, use an onplayertouch>setplayertransform event. On that same brick, use VCE to count (counter1) how many enter and set a client variable to true. Then, on another random brick, use minigame events onminigamedeath and onminigamekilled>ifvar>entered>1 onvartrue>counter2, then onminideath and onminikilled>ifvar>counter2 == <var:mg:counter1> onvartrue>mini>end
I think that should work.