Accessing the room would give you a new quest: 'Joseph: The Summoner' which lasts for 30 minutes. There will then be a server-wide announcement saying:
Joseph: The Power from the other realms has descended upon 'Player'!As soon as you enter, you will be reminded by Joseph:
Joseph: You have approximately 30 minutes to unleash your power!
Joseph: Remember... With great power comems great responsibility!After 30 mins, you will automatically be warped out of the room, and there will be this server-wide announcement:
Joseph: The Power has left 'Player'!Likewise, the same message above will be announced if you decide to tell Joseph that you're done for now, which is how you get teleported out of the room.
Getting teleported outside, whether it's because of your choice or because the 30-minute timer ran out, all the monsters will disappear and cease to exist, whether or not you were already fighting them.