You may encounter a Treasure Hunter standing next to a portal in the Stinging Winds. Talking to him allows you to enter the The Crumbling Vault through a portal.
The location you’ve just been teleported to is vast and additionally you have to worry about the time limit. Don’t waste your time fighting all the monsters and instead try avoiding them when you can. Find a second portal which leads to the The Crumbling Vault Treasure Room and immediately use it.
Once you’ve been transported to the The Crumbling Vault Treasure Room you can stop worrying about the time limit and the event will officially end. Naturally you should spend some time opening crates found in the area. Once you’re done use a portal to return to the Stinging Winds.