As posted at Everest Mystery:
Postmortem: So my guess is that Irvine achieved his weight reductions by breaking the seals between the backup bottles and the regulator with the idea that he could reseal a bottle to a single regulator (one at a time) with a good spanner. This is why they broke down the rigs and "saved" weight. (he got rid of the "redundancy" of multiple regulators--about 5 lbs worth per rig).
However, after the first bottle, he found that in the extreme cold he could not achieve the sort of seal that he could at base camp (probably due to stiction/Blish effect) which was outside of his undergraduate education. There is some evidence that they exactly had this problem when testing things out and did not realize the significance of stiction.
This would have given them 4 hours of O2, and not much more. Thus, they would have reached the point where the No 9 bottle was found and spent the next three hours beating the hell out of the remaining bottles with their spanner. A 1:27PM, being out of O2 for some time and frustrated beyond comprehension, Mallory took one wrong step.
And that was that. Odell may have seen it--I think so. Because he knew enough to try to poke around at that time but also enough that they were dead or about to be.
Note--we know that Irvine disassembled the rig. So this idea can be tested before running off and accusing anyone of lying (or worse yet--the arrogance of undergraduate ignorance). I am only proposing this idea. But it answers everything as far as I can see. The bottles at that time were not able to be resealed under the conditions of the dead zone.
The fact that many of these bottles were already breaking seals in Tibet is a testament to the limits of a threaded seal at that time and the variability of the threads under extreme conditions, not that some bottles were "bad" and the others "good". It's all about confidence limits and statistics. At two sigma you may have a number of good ones, that goes down exponentially at three sigma. Irvine would not have known this.
They never came close to the summit.
