Ukraine

All i can remember was it had to do with your MOP gear- GAS! GAS! GAS! - no clean seal, u ded.

which brings back awful memory of the tear gas chamber in boot camp....i dont know wtf i was thinkin that i could get away with name, rank and ssn in one breath and the Drill not being able to tell lolol. Took a shot to gut, one giant inhale and rest was history.
I had the same experience. I had beaten the game many times, but one time I screwed up and took in a deep breath. Had to helped out of the tent and the strange thing is I could inhale all I wanted but couldn't exhale any air. I had to basically try and belch out air and it took a while. I used to look at others for making that mistake and this time it was me.

To top it off I was made the NBC officer for my company so I had annual refresher training and, of course, the tear gas tent, the charcoal-lined suits in summer, etc.

To the original point, that was a big reason for the no facial hair. So the mask could seal.