Hyenas can be tricky. GTFO from that ledge ASAP and make sure to have both absorb shields on. You can always reset in the safe zone rather than dying. Boss fight can be easily reset as well. Ideally you should combine this (7.5ish mins) run with Lasher runs. Use alt or 2nd account character to reset yourself to entrance obviously in DM:E.

Never use frostbite - you will die.
Don't be too low without ice barrier vs boss - you will get one shot via enrage.
Don't attempt a messy pull (resists, non tightly grouped mobs etc) - Safe zone is easy to get to and saves graveyard runs, there are no trophies for speed on this farm as you will hit lockout limit.