[glfharris]

The foils can break, leaving a sharp tip that is more able to pierce protective clothing.

[AzzieElbab]

the blade doesn't event have to be sharp to go through a mask. I had my mask pierced by a rapier with safety tip still attached. Hell, a blade may break while bending against a mask.

[tianqi]

That sounds horrible, I hope you were okay. Also it's hard to imagine. What brand and model of mask were you wearing?

[AzzieElbab]

Some very rusty made in the ussr brand