Id never count it out as long as the equipment was available. To put someone back in the water isnt just wack a reg in there mouth and send them down it takes gear and backup. Needs O2 for the patient and something better than air for the observer. FFM for the patient at least in case of convulsions. Shot lines and trapeze. A means of hydrating and staying warm for inexcess of 4 hours in the water you just got out of. Tropical water is cold when your hanging around doing nothing.
When your 6 to 36 hours away from a chamber id always be prepared for it. The risk to me is worth it. For under 6 hours id consider it on the day depending on the case.

Matt