Death Knight trophy help

Hi , i just got the 4 runes on Nightmare mode. Of coirse there was some ennemies on the Runic Nexus after going back with the last rune. Anyway , i know the Death Knoght Head to get the tropht ( and unlocked the bloody nightmare difficulty) is hidden in the Shattered Mind level. How do i go back to this specific level to get the trophy ? I don’t want to enter the teleporter level who require the 4 rune if it’s a no return point and i can’t have the trophy in one playtthrough.

I already did the platinum on Quake , i just want to finish those 3 trophy of the dlc.

I like Dawn Of The Machine for the most part so far but some level were way too long and too confusing sometimes.

It’s still good , but could bd better.