While we were waiting for some guy before starting the last encounter, a necromancer in our group pulled with his pets and then ran out of the boss room. When the encounter reset, the doors did not open again.
Off topic, but might as well add it here:
Necropolis boss dies off dots as he finishes cast on prism blast. We are all down with the loot boxes on the platform. There is no way to get back up and loot the boxes.
Hehehehe had that 2 times already in necropolis, use our hint:
If you see, the boss is low on healt and it will be close with death and blast, let your caster/priest go spellweave and he will not be kicked down by the blast and can open the box for the group...
1. (as posted earlier) Everyone dies and remain dead (jump of ledge or aggro a mob).
2. Everyone revives and goes into hide. I've experienced that many mobs tend to reset properly if everyone in group/raid enters hide.