tarponchik
Contributor
I guess, the assumption here is the mask is lost when the strap is broken.A mask can be kept on without a strap or broken strap.
I also suggest a trick. Suppose you've lost your mask in the deep and you have no spare. Coming up, all you'll need is to check your depth gage. Keep your face down, fold your left palm into a tube, press it to your face around your left eye and get some air bubbles into this "tube". Once filled with air, you'll be able to take a look at the gage.