It's Vivai's fault.
Sure, he flipped both switches that were supposed to redundantly disconnect the pelletizer's power supply before he opened its case. Sure, the case shouldn't even have been able to open with the power supply connected.
It's Vivai's fault anyway because it's his damn pelletizer. Or at least he's acting as though it's his, having elbowed his way six months ago toward being in charge of its maintenence. It can hardly be the pelletizer's fault.
Vivai thinks a psychedelic, subverbal version of this in the short minutes between bumping the pelletizer's power button with his hand in the roller (a few seconds later someone makes it to the STOP button) and losing enough blood to be dead.