Viscous Fallout

Gnomeregan

Launch Bay floor

Descend with the group and clear a fighting space around Viscous Fallout before pulling it. Attacking enemies below a walkway can send them through other packs on their way up; move the party to the floor instead. Finish any collection-phial sampling here before clearing the creatures it needs.

Viscous Fallout

Elite Elemental

Viscous Fallout is fought on the Launch Bay floor, where an uncleared irradiated pack can turn the pull into a fight across different levels.

Tank
Pull Viscous Fallout into the cleared part of the Launch Bay floor, away from the remaining irradiated packs; do not start the fight while the group is still descending.
Healer
Move onto the Launch Bay floor with the tank before Viscous Fallout is pulled so the fight does not begin with the tank below you and out of reach.
Damage
Finish the enemies around Viscous Fallout before attacking it. Follow the tank to the floor instead of opening from a walkway and drawing enemies up through the dungeon.