Not really.
First, I agree that getting off the loop and taking a sanity breath is clearly the safest option and would be my first choice....but....at least with OTS CL's...you can open your CL exhaust valve, roll so the valve is up and dumping gas, exhale, empty the CL and flush with the ADV while holding your breath for a few seconds.
Quote: (Originally Posted by
lizardland)
If you have a Rebreather with an ADV then a flush means breathing the loop volume down far enough to get the ADV to fire. That means breathing down a gas that might be hypo/hyperoxic. It may only be one breath but that's all it takes.