I've researched this method a lot, looked at all of the reports from people doing it who ctb, or didn't, the reasons for their failures, etc.
My belief is that if you follow the regimen, i.e. no food in stomach, have abstained from fluids for 2 to 3 hours (or maybe more), then the SN should go straight to the intestine, even without meto, and since your body will be wanting water will be taken up quickly.
People who have a cigarette after taking it (don't know if this helps to reduce O2 faster or does something else, or is coincidence) seem to pass out faster, as do those who are upright, either sat up or standing up - the low BP seems to make them feel dizzy faster, they then go out faster.
Those people seem to feel no ill effects e.g pain, they start to feel dizzy and within 2 to 3 minutes appear to be out cold, at which point they are hopefully unaware of anything else that happens.
That is all anecdotal, and is my belief that if you drink it then lie down it'll take longer to pass out.
The agonal breathing is a brain stem action, not tue breathing, and happens when the body is in trouble, ie is starting to die, I think at this point they will know nothing. This also seems to happen fast from passing out.
Until you experience it though it's all hypotheticals, even if based on observations.
