Firefighter (25 player)

Don't forget to bring your Fire Extinguisher before attempting this achievement!

Kill Mimiron on his hard mode.

Push the big red shiny "DO NOT PUSH" button prior to the fight to activate the self-destruct mechanism. This gives the raid 8 minutes to kill Mimiron before the raid is wiped. Also gives all Mimirons vehicles the Emergency Mode buff, increasing their health and damage done by 30%.

Now why would you go and do something like that? Didn't you see the sign that said 'DO NOT PUSH THIS BUTTON!'? How will we finish testing with the self-destruct mechanism active?

Pressing the big red button changes the fight in many ways:

Phase 1:
In addition to getting increased damage and health, Mimiron can also spawn 2 or 3 patches of Doomfire on a random person in the raid. The fire attempts to follow the person closest to it. The fire moves every 3-4 seconds (there is a delay).

Phase 2:
The flames continue to spawn through this phase. Mimiron himself does a melee-range AE pulse that eliminates fire in the inner circle where his vehicle comes up from. He also throws a big Ice Bomb at a random spot in the room. This detonates after a few seconds dealing around 8000 damage, knocking players hit by the explosion away from the bomb, and extinguishes any fire near it.

Phase 3:
A new type of robot spawns during this phase. They run around the room, pausing at certain intervals to extinguish patches of fire throughout the room. They also have an aura that silences anyone near them. The most popular strategy is to just kill these new robots as quickly as possible, as having them silence your healers can be very dangerous. Also, Mimiron can only spawn so much fire. If you kill the robots quickly, you only have to manage the fire that has already spawned, giving you an advantage.

Phase 4:
I have limited experience on this phase, but I can still provide some insight. The fire continues to burn in this phase, so it is still crucial to watch your step. I cannot remember Mimiron gains any new abilities in this phase, but I do know that he has all of the abilities he has in normal mode. Also, thanks to the recent fixes to the encounter, the base of his machine will now be stunned whenever the middle starts to channel the Laser Barrage, making things a lot less hectic!

Edit1:

The shock blast does not do a disorient effect. As far as I can tell, it is the same as always (you get hit, you die!).

Edit2:

There is indeed a spawn cap on the fire. Also, in Phase 4 the fight is no different from normal mode, with the exception of the fire on the ground and the Ice Bomb ability he uses from his arsenal in Phase 2.