Confusions are seen regarding Rush feature in City Events after the last update, and here are some tips that could prove to be useful.
1. There are four durations: 1/2/4/8 hr. The costs and rewards are proportional with the durations - the longer you Rush, the more you gain.
2. Once you're in, your rewards for the current Rush session will be calculated according to your current deck and the duration.
3. The amount of rewarded Boss cards depends on how many bonus-generating cards are in your deck, so keep an eye on those cards specified in City Event notice!
4. You may not get any Boss cards if your deck doesn't contain any bonus-generating cards.
It is recommended to only use Rush feature in City Events when you have put in all your bonus-generating cards, and it's always wise to check the reward preview before you proceed.
Hope the explanation above could help clear all your doubts, and we wish you a bountiful journey in all City Events to come!