Do you think we should just give the diver a few minutes of bail-out because he might be too cold to care/incapacitated after that!!??
Not at all, it is a simple trade-off. Increased failure modes, primarily various types of scrubber and loop failures, reduces bailout capacity from minutes to seconds. Bailouts are a sat diver's very last resort and simply has to work. So far, I have not been able to find any report where a diver has not been able to make it back to the bell on open-circuit bailout. I have seen and heard many reports of sCCR failures in sat diving, mostly wet absorbent and damaged corrugated hoses. Fortunately none have been fatal or even close with the possible exception of Barry Cannon on Sealab III in 1968.
Significantly increasing bailout capacity has very little value if the hot water also stops. This debate has been going on for decades. As I have written several times, nobody would be happier than me if a clearly reliable solution for this problem can be found. So far, hyper and hypothermia have killed more sat divers than loss of gas. My comments have nothing to do with being ill-informed or stuck in the past.
These commercial units are not like recreational eCCR.
I am fully aware and nobody has suggested that they are. Unfortunately, the Divex units can't really be all that much more ruggedized than recreational and military CCRs and still function. It is a very difficult challenge.
One of the most important lessons I learned very early in my sat diving career is adding "safety" systems that also add potential failure modes and/or complicates rapid diagnosis of failures actually reduces diver safety. Sadly, this has been proven over and over. It is very rare that injuries related to system failure are simple. More often, three or more system and human failures conspire to kill divers, usually in ways that have not been seen or anticipated before.
There is nothing revolutionary in any of the Divex rebreather bailouts. Refinements for sure; but hardly anything of significance that could not have been produced decades ago. Larger bells and bottom hatches on newer sat systems is more of an "enabling technology" than any other factor.
He didn't! He regained consciousness after 2 breaths from the bellman.
Not exactly, pouring hot water on him began before the bellman could get the hat off and in position to administer the breaths. The bell atmosphere being blown into his lungs was also not far from body temperature. Both were critical factors.
Not all sat divers rely on HW suits for thermal protection either so if HW is lost this 'cold shutdown' won't happen.
I would be interested to know what sat systems you are referring to. I have never seen or heard of a working sat diving operation that wasn't entirely dependent on hot water for heating suits and the bell. In my experience, hot water failures have recalled a lot more divers to the bell then loss of gas.
Most sat systems that are permanently installed on DSVs (Diving Support Vessels) get hot water or steam as a shipboard utility. The sat system handles heat transfer (for steam), mixing controls, temperature control, and additional pumping capacity. There is almost always full system redundancy up to the manifold feeding bell umbilical. Portable and semi-permanent systems usually have redundant diesel-fired boilers.
Do you understand how a sat system works?
I know that this question was not directed at me, but I think it is fair to say that I do. I was extremely fortunate that my career included being a sat diver, support technician, system manufacturer, project manager, product designer, and consultant.
Your analysis is considerably more enthusiastic than any of the sat divers I know, including those with hundreds of hours locked out on the Divex SLS.
Irrelevant as the unit we're discussing isn't a CCR!
Specifically it is a semi-closed circuit rebreather, commonly abbreviated sCCR. Mixed gas sCCRs have been around a very long time. In fact, the US Navy Helium Hat that was based on the Mark V dates back to the 1930s is a mixed gas sCCR. Unfortunately, I had to train in one of these pigs in order to qualify for sat training.
The operating principle down to the venturi is the same though refinements are significant.
) you'll see it's a cartridge system that could be passed in and out of the chamber through a lock and swapped by the divers themselves if required. They are not sat around for days/weeks. They are diligently maintained by well trained people. Again maybe a bit of rec eCCR mindset here? And, although as I've pointed out here not really relevant, I can charge the scrubber in my recreational eCCR and leave it for quite a while and it's stays dry. If yours doesn't you might want to remember to close the loop 
. However the 'deep ocean' where temp is 0-3°C is generally taken to be over 1000m in some parts so there'd be no sat diving there! Not all divers rely on HW suits for thermal protection either so this 'cold shutdown' won't happen. And certainly not before all the gas is gone in an OC set. This thermal issue is a bit of a smokescreen by a previous poster and I've already debunked the example he used (which is the only one in existence as it was a one-off).
