It was also kinda a bit of a challange. But all this is off topic.
Howard, I know you do lots of hardhat work as well as scuba. Have you done any Hookah diving? Just curious.
Hookah, Hardhat, FFM, Rebreathers, OC, you name it.
My answer, explaining that you can EASILY​ exhale is accurate. Don't take my word for it... ask ANYONE who dives a rebreather. It's done every day.