bipolarbear
Contributor
I think this is unfair on OP.You've got 30 dives, and all your own gear, yet you consider yourself a newbie and you act like one.
Not monitoring your air, not taking the DM's octo when you were already breathing hard were huge mistakes, offering your primary reg to the DM to see if you were doing something "wrong" when you were obviously OOA, completing your safety stop when you AND the DM are BOTH out of air were others, although that last one is on the DM although it's hard to believe there is such a level of incompetence in a supposedly trained professional that would require both of you to make an emergency ascent from safety stop depth and risk an AGE because you just HAD to complete that last 60 seconds of safety stop following a relatively shallow dive. I don't think I've seen this level of combined ineptitude in a single dive.
Where was your dive buddy when all of this was happening?
Based on the the pressure chart the OP has provided (which no one seems to bother reviewing), and the fact that there was no catastrophic gas loss reported, it seems quite clear that what OP experienced was some obstruction / clog in either the valve assembly or the first stage itself. Can be caused by rust, water ingress or other contamination.
We can discount tank roll off (which would have become more breathable as OP shallowed up), free flow / gas rupture and OP inexperience (because as they rightly point out, it's not humanly possible to consume 110 bar from an AL80 i.e. over 1000L of gas in two minutes at 20m).
Agree that safety stop should have been skipped in these circumstances. Also very confused how DM did not have sufficient gas to air share a diver to the surface at the halfway point of a recreational dive. More blame should be attributed to the DM than to the OP here.
OP should have the tanks and first stage inspected. If there is contamination then second stages should probably be looked at also in case some of the particulate has migrated up to the regs.