Charlotte does not like being ordered to wear a face covering - she does not like being muzzled by the state - something of a contradiction since she is happy enough to be muzzled in the bedroom, so she decided that if she has to wear one, she would wear something completely ridiculous and over-the-top, such as a gas mask. I guess that makes this particular clip something of a political protest... you've gotta love the slogan on her T-shirt, much better than Boris's!