You are describing a situation where you must choose what sucks the least. What preparation and skills are available, how far is a chamber, and what are the symptoms?
Oxygen for decompression onboard, 500 miles from the nearest chamber or chopper to get you there, competent safety divers, and a mild joint pain? I'd be in the water sucking from the green bottle. Five miles offshore, CNS hit, inbound Coast Guard chopper, 20 miles from a hyperbaric hospital unit, onboard a typical sport diving half-day boat? I'd be lying down on deck patiently breathing Oxygen.
The problem is the huge variability between the two circumstances described above. DAN's recommendation is likely the least of the evils in most cases in the recreational setting. However, when you are the one at risk, I believe it is prudent to know more than memorizing a general recommendation rather than interpret it as a rule from God.
I know a commercial diver and supervisor who treated himself in a chamber at the shop (no names, OSHA would have a cow). Should he have waited for help to arrive? Knowing his skill level and knowledge of the systems, IMHO probably not. My answer would be probably yes of it were most of the divers that worked for the same company. He knew another supervisor was on the way and he had been hit in the same knee before. Was it good, no. Did it suck less than waiting 45 minutes? In this case, probably yes.
Short of staying above 30', there is no guarantee any of us will never get hit, but you can dramatically decrease your risk by being conservative when choosing your dive profile. Even if you are not 100% successful with this strategy, the severity of the symptoms are likely to be far less.
