I’m just seeing this now and checked my achievement. I did this on 9/28/2024 as a 613 Fury Warrior with around a level 45 Brann I believe.
This encounter is a big song and dance routine of paying attention to hazards around you, critical casts to counter/stop, add bursting, and consumable (Brann potion) management.
Success for me came when I was focused solely on execution of these things and not worrying about the HP % of Zekvir ??.
Good luck friends! I would imagine having iLvl in the 620+ range is a bit easier but understand there are many different classes/specs. YouTube is my friend for finding strategies and understanding areas I need to improve with.