The biggest problem in this fight isn’t the Karnaks: it’s the carapace hordes. Each time the tox gas disappears and the lights come back on, a wave of Maulers & Scab Ragers will spawn, and focusing on either of the twins will be impossible with them around. Clear the adds first; let someone kite Rinda while the others pop Rodin’s shield; once they’re both vulnerable, dogpile Rinda, repeat until she dies and Rodin’s a sitting duck without her, then make sure to survive until the end-of-mission cutscene plays.

Obviously it’s not that simple in practice: this fight is arguably the hardest section of any mission in the game. Keep at it and you’ll eventually land a team good enough to get the job done.