Orange Grove fatality?

[nakatomi]

With only one tank for DiL and BO, you're in trouble when the burst disk craps out or you rip a hose badly. Seems unnecessarily risky, imho. Why not just take a 2nd tank?

Risky? I think it's worse than that. If the first stage falls apart you have zero diluent and no inflation for the BC or dry suit (which completely sucks in a cave where it usually goes up and down on exit).
You also have no bailout. In other words without a buddy you're pretty much dead.
With a buddy it will at least make for a very miserable and adrenalin-infused exit.

 

[The Chairman]

If the first stage falls apart

Most rebreather divers make judicious use of isolators. Tink, it's off. Easy enough to breath off of it you have a free flow issue with the first stage and you have to bail out. Hose or other issues? Not so much. I won't dive a rebreather without a redundant bail out/off board dil bottle. I won't dive a rebreather in a cave without two of those. I'm a skeerdie cat.