Protect yourself from Covid while rocking the Daft Punk Look

It uses fans to blow air through HEPA filters. Good that they also filter the exhaust air. The FAQ says nothing about safety measures though.

Questions would be: does the helmet automatically open in some way if the battery runs out? Is it "default open" and only held closed while battery power is available?

If not and the battery runs out and you try to breath in this thing, the dead space [0] is liters instead of hundreds of milliliters. It would be like breathing into a bag.

Any ideas on this?

[0] https://en.wikipedia.org/wiki/Dead_space_(physiology)