IDK, that's how it is in real life. The purpose is to strategically try and avoid tiebreaker situations.
Im pretty sure in real life everyone is up for elimination unless they have individual immunity, also this isn't real life you can do it however you want. In my opinion it would be better to do it either one of two ways choose someone at random and whoever they voted for gets eliminated or randomly eliminate one of the people in the tie.
I guess its your game, though i would hate to be metalx right now.