How about like it's a competition kinda like the infernal war idea except only 100 ppl can only enter the last room. You have to keep fighting other players when u enter the next room until u pass all 50 rooms. If u dont finish and ur at the last rooms, u stay there until the next time u login and u recontinue where u were before. The faster u finish though, the faster u get to the special shop. Personally, it'd be better if there are 150 Golden Yetis.
I posted this in a thread. Just wanted to share to make it more even for those who can't get the yeti.
How about a tournament between Alphas only, Betas only, Gammas only, and Deltas only. The more chhevos, the more u get into special places through the tournaments, but u can only go to whatever ur first phase was so the feauture cant be abused.