My main issue is that in most cases it won't the stun gas won't knock people out with one dose... 10 stun on an average body 3 or will 3 guy they will get one hit and take 9 stun damage and stay up with 3 points of wound penalty but still up.
In a normal situation the gas with an onset less than 3 seconds and a duration of 1 min would hit a regular guy 20 times in 1 min definitely killing him. How do you do with that in the system?

Um, nine boxes of stun damage should be adequate to neutralize noncombatants? The damage only procs every one minute, so the non-coms don't die, they just spend the necessary minute crawling right the fuck out of the gassed area and to safety. Everybody wins? Having the gas only go off once every minute (as opposed to once every turn) as opposed to once every turn also keeps the combat power of Neuro Stun gas grenades in check, because they are already Force 10 Stunballs with no drain that anyone can throw, and IIRC you don't even need to hit the target just get it near him. Not as broken as SnS but still pretty good.

That is how I'd handle it. I don't know if that's the right interpretation of RAW. Probably not.

Reposting from my earlier response, one page back.

The core book reads,
"Concentration
If a toxin is applied at concentrated levels (more than a
single dose), the gamemaster may increase the Power of the
toxin as he feels appropriate, as well as increasing the damage it
causes or its other effects by an appropriate amount.
Likewise, if a character remains in contact with a toxin over
an extended period, such as being caught in a gas-filled room
for several minutes, she may receive an additional dose and suffer
stronger effects (or have to resist the toxin again)."

For Neuro-Stun, it reads,
"This colorless and odorless knockout gas is used
for emergency-containment conditions. Neuro-Stun comes
in different concentrations. Some become inert after only 10
minutes of contact with the air; others become inert after only
1 minute. Wind and other environmental conditions may disperse
the gas more quickly."

I'd just go with gas grenades, having the version of the gas that goes inert after one minute, by default. This way, You'd be correct to just increase the power slightly.

In the situation the GM laid out for what the 'runners were up against (and I've thrown something very similar to that at a group I was GM'ing in the deep dark distant past... ) I would have had to nod my head to being outmaneuvered by a 'runner.

Yes, I would consider upping the Notoriety some for this, but since it was a non-lethal way to move through non-coms, it shouldn't be too crazy...

If you think about it from a 'runner's point of view, given the situation described, that was a pretty good move on their part to keep the death to a minimum and the mayhem high enough to pull something off...

Sometimes you just have to ignore the rules. If the aim of the grenades was to take out the non-combatants without killing them, just rule that it works. You should only role for key NPCs to see if they make it out before going unconscious. Of course, in a room full of people, it's always possible that someone breaths in too much of the stuff or is allergic to it and croaks, but that is GM fiat.

Drama, story and the rule-of-cool should all supercede the RAW when required/necessary.

Agreed.

Or, you can read the rules, and realize that gas doesn't work this way.

If Neuro-Stun was meant to be 100% fatal why would it be called Neuro-Stun or do Stun damage at all?