If you die on the floating platforms where you first find the boss (for me it's always near the orb stand) you respawn all the way back on the top of the cliff before the portal. On respawn you're greeted with TURN BACK 04 03 02 01 DIE! You cannot make a 12 second run/jump/use portal in only 4 seconds. You also can't get out of this until pulled into the last part of the boss fight just before the chest. Try getting 50,000 like that! I have video
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To clarify: Die in Adytum, respawn in the Ascendant Plane, die from being out of bounds, repeat until the last part of the final boss fight.