Dodge Mai Trin's various attacks, break her defiance bar immediately to gain a damage boost
50% split: small adds spawn, kill them
33% split: two elite adds spawn - dump all hard CC the southwest one first since it has a huge breakbar, then kill northeast, then back to southwest for more CC. Stand in green circle when it spawns
Mai Trin at 10%: Scarlet Briar spawns, dodger her orbs, jump/doge shockwave. Same elite add splits happen at 80% and 40%
If you get a blue line over your head / blue border on your screen - run out or it wipes the group
60% and 20% Deathray: 3 rotating "safe" areas spawn and Scarlet appears at the edge - stand where she wouldn't hit you in a straight line attack to await the correct safe spot - the other two get nuked
Photon Saturation: misplayed spreads/aoes give a stacking max-HP reduction - spread properly to avoid unnecessary damage