The scenery in front of Aster's eyes changed from the resting area in that temporary city, to an open area at the top of a platform that was floating above in the sky, Aster looked downwards but the everything below the platform was covered by clouds.
Mikaela and the elders didn't enter with them, there was a barrier covering the platform and a message was displayed on it.
Basically, it explained that the name of this event was "Treasure Hunt" and that it was prohibited to use any kind of spirit treasure besides the ones that could be found here, spatial rings included.
Besides that, it listed the classic rules for events in the sect, which basically prohibited killing, but fighting was allowed, as for the objective of the event, it didn't say anything besides "Reach the exit" and that they could keep the treasures they managed to take with them to the exit.