>>12812974It's run on a kayfabe lottery system. Cody was just the first to put his name in the running. Once they have 30 names they populate the list and on the night of the match each contestant is randomly selected until they announce the 29th entrant. The gimmick is that everyone backstage knows they are going to be in the Rumble, but no one knows when they will be called to run to the ring until it is announced to the audience. It doesn't really work like that because some dudes start running out the curtain the split second their music hits, but that is the conceit.
