Might be a dumb question, but…

If I’m doing panic zealot in a party, i die and then I return to the boss arena while my party members are still fighting it, can I still get the reward?

 

Probably? But the chances of you finding enough items for the zealot and still going in there and not dying is quite rare

 

but what if i already have like a stack of the summon item, which means that I can directly return to the place?

 

Yeah that should be okay. As long as they haven't killed it yet. I don't think there's multiple zealot rooms for multiple battle instances.

 

instances don't exist if you are on the same server you will end up in the same boss room and if they are still fighting you will join their fight