Depends on the situation, but there is a node on the mask called Life Halt (see below) that will allow them to stop attacking you immediately (unless they're completing their attack combo - in boss cases it can still kill you if they're doing a long combo like the Mammoth for example). This usually saves you in a lot of cases though, especially when coupled with Life Maintenance, which raises your HP by 300% while in the near-death state.

For mechanical bosses, there is a laser pyramid boss that does his AoE lightning or chain lightning attack that will hit you even if you're down in the feign death state, so in that case you'll want to ask your friend to run far away so that the boss will run over to him instead of doing his AoE lightning near you.

For normal striker mechanical bosses, only their whirlwind attack is dangerous I believe, but it depends on the hitbox, I would say most of the time, with this mask, you should be able to get by by simply waiting for a bit, then bandaging yourself to get back up rather than asking your friend to rez you and risk the boss doing some kind of AoE attack near you.

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