I filled up all my chest slots in Arena 6 but then went on a losing streak and ended up in Arena 5 again. The problem is, I want to have a shot at those Arena 6 cards so I’d rather not spend my unlock time opening Arena 5 chests.
When one of my Arena 6 chests finishes unlocking, I don’t open it. I can start unlocking another chest. All of my chest slots remain full and I’ve still got at least 9 hours (if all my chests are Silver) to break that losing streak.
Once I get back into Arena 6, I’ll open all of those unlocked chests and start filling the slots with new ones.