Vampires are not dead. They are undead. ‘Iw tlhutlhnISbogh HeghHa’wI’pu’ chaH.
And, it’s not altogether certain that they need to breathe. I mean, what would happen if they couldn’t breathe? Would they die? If killing them were that easy, why bother with sunlight, or a stake to the heart? Just gas the suckers.
Have you ever seen a vampire movie where the solution was to gas them?
charghwI’ vaghnerya’ngan
rInpa’ bomnIS be’’a’ pI’.
Agreed. I was recasting the idea, not the specific grammar. It’s not like you can breathe while being dead (except for vampires).
Voragh
So to re-cast your first example, I would see nothing wrong with:
Suvlu'taHvIS batlh potlh law' yIn potlh puS [or]
Suvlu'taHvIS batlh potlh law' tlhuH potlh puS
But neither of these express "breath(ing) while living".