Everything in this game is fixed. From chest draws to what you get from group missions or in survival. Card draws are supposed to make you feel like its random. I've been doing survival with 5/6 rewards for about 2-3 weeks now and rarely get the item that's on the left side, which is most of the time a rare ninja shard, coupons or summoning scrolls. In other words, items, which you would have to pay for.