Just checked my log for that "half run".
First pull all but me triggered and died to Sanctify ... (yes, in a +16 tyrannical people with "some" score still do that apparently).
Second pull 1 died to Expel Light + Arcing Bolt (had Prydaz, but got no heals), but 3 died to Eye of the Storm - apparently learning fights is a thing.
Third pull they ALL died again after taking dmg from Eye of the Storm, while 3 of them needed an Arcing Bolt/Expel Light to finish them off.
Basically the key-owner (healer) screwed up healing, while 2 dps had not enough survivability on their own and the healer himself.
Guess I should pay more attention to reading raider.io and mph - they had 0/1/3 +15s timed runs ... so basically clueless about the environment.