Low ( not really ) breath keeps interrupting tasks

My rancher keeps going into my hydrogen room for drakoes to shear or wrangle them and getting interrupted half way through to go breathe oxygen, even though his breath is only down to like 68%.  He only has to go through like 4 tiles of hydrogen and an airlock to reach oxygen, and he keeps needing to go back before finishing one job, and the drakeo wonders off.

The Radioactive Panopticon.sav