LOL, nothing wrong with what you wrote I presume but you literally just got me to lol. There is a (somewhat dismissive) saying in German for someone who is bareley going to make it, if at all (in a race, situation, game, life, whatever).I'll just throw this out there. You can breath off a DiveAlert whistle. I'm in no way suggesting it would be great, but if you need gas and all you have is a bad reg and a DiveAlert, that whistle will provide.
Something along the lines of "He / she whistles out of the last hole". (as in that's it, then there is no more)
Your words just put the perfect pictorial to that in my mind: A guy making his way to the surface honking away, sipping air from the air-whistle (ok, horn)... could not help it but to lol.