The morning of the summit attempt one party member was weakened, with nausea, a headache, malaise, difficulty talking or performing simple tasks, etc.. classic altitude sickness. I was about to take this individual down when I noticed irregular breathing patterns. We focused on deep, regular breathing, which seemed to increase the saturated oxygen in the blood, because all symptoms were significantly reduced, and the individual summited and descended with the group.
With no offence intended, but this is not a smart idea. If you have symptoms of AMS you must not ascend. That one individual may have gotten away with it, but others will run into serious trouble. People have died at 10000 feet from AMS.
I've been to around 6000m/18000 feet without symptoms (if you don't count lack of breath and difficulty sleeping!). But did it *really* slowly. I followed the 1000ft/300m per day rule, plus one day of acclimatisation (same altitude sleep) every three days. Drank buckets of water, though not sure whether that helped (many think it does).
The Nepalese are big believers in garlic helping acclimatisation… so just crunch away on a few cloves on your way up the trail ;-)