Why do people not understand A8?

[whereismymind86]

I still don't know what to do when the AoE circles and Arrow drop at the same time in A8 last phase.
For some reason I always die.
It's super confusing. At this point I think it's because I'm going in front of him and getting hit with something, but I still can't be sure. Thankfully I'm the only one that dies.

Its the same mechanic from the final boss of Void Arc and a few other places, stack on the party to split damage similar to the dual laser cannons really. It hits hard but shouldn't be fatal unless you have a few vuln stacks from the raising/lowering platforms or something.