My highest death was 20 on a priest. On that final ramp ascent to Van Cleef, someone pulled extra packs. I dutifully healed the tank, who ran instead of establishing aggro. The mobs followed that healing threat and beat me into a pulp.
My pally is quite a bit longer lived, but had her closest call at level 25 in BFD. It was a terrible, sloppy run: two hunters with pets out, a VW warlock, and everyone “off tanking” mobs away from me, the tank. One of those mobs started running outside of HoJ range, and it pulled several extra packs. I tanked as long as I could with my heals and LoH before I had to bubble and run. We lost two.