The event quests are nearly filling one day to fullfill one quest each, if you want to unlock legendary room.
I had 5 Quests left, then: Find 250 Epic Cards. Next quest: find 250 Event rare cards: (Faith Healer),
If you do not spend gems to reload, you have to play 13 times against the 2nd event openent.
Means 13 h waiting, nearly imposible if you have a job and real life.