And what happened is perfectly normal, it's simply court order whihc uses up 2k+ focus (I think) and that damage is achieveable with the be seated debuff on you which doubles the damage you take.
My bad, I believe it uses up 1100 focus actually, but still a LOT of focus.
Anyway, the easiest solution is just to kill them at the same time, because duty uses up all 2k of their focus, and pretty much the only way to get it back is to use state of emergency, and even then it takes about 2 turns to get enough focus... You can have roald silence him or if you're a hydro mind freeze him.
Depends what class. If you are a Bio then just use break , if you have it , to stall one. Just let Roald silence him then. But if you are a Hydro then just use mind freeze or try stunning them. If you are a Psycho just use shock therapy. But the main focus is make sure they both die at the same time. If one of them dies they will use "State of Emergency"