This is for the LEGITS.
I'm sure you could possibly MMC them if you have hacks.

Step 1 : Dimensional Mirror. Choose evolving world.
Step 2 : Get into evolving world. (Talking to the NPC. You can go in 5 times a day).
Step 3 : Go to the room 3 (Mine shows HECTORS. They're most likely going to be MUSHROOMS unless you used an item to change the mob appearance like I did)
Step 4 : The reactor in the middle every 20 seconds i'd suppose will start making all the mobs go towards the middle.
This is where you take advantage of it. I dont know if its a glitch or if they wanted to do this, however, its really helpful that they put this in.
Step 5 : Kill them all until it stops vaccing.
Step 6 : Loot everything (I used a 2x drop buff)
Step 7 : Wait until they get vacced again, or just kill them flying around.
Step 8 : Profit.

Good luck in this new event map thing.