you finally beat Melvelous the Magnificient for the first time, 30 seconds before the server goes down for maintenance.
I beat Temple of Scales, which I consider to be one of the hardest quests, after the 10 second warning. My characters leveled, but I had to wait for the server to come back up to loot the chest. There were 2 Epics and a Legendary inside, including the club reward.
I once experienced a random unannounced server disconnect* a few seconds before beating Melvin in an adventure. I'm pretty sure it was he who pressed the reset button, though he denies it vehemently. *maybe the problem was in my connection, but anyway.