My impression from the Moscow Theatre was completely different. Gas proved exceptionally effective, ending the siege with minimal (as compared to conventional assault or even waiting the kidnappers out) casualties, it was the fucked up post-operation medical response (delayed and disorganized) that actually killed most of the hostages (by something as simple to avoid by rescuer as drowning in your own vomit, no less). All the opinions I read on it agree it was well executed and had the medical help post it been adequate, it would have been one of the most successful AT operations in history.
Except that it took two and a half hours
before any of the hostages could be removed from the building. It took that long to kill 30 or so gas-affected hostage takers and clear the building of explosives: a portion of the hostage-takers were still conscious and fighting while most hostages were knocked out. Some terrorists had gas masks, which none of the hostages will ever have.
It's far from clear that it was the medical response which caused most of the deaths ; In fact, death certificates were deliberately filled out vaguely, listing "terrorism" as cause of death, so it might be impossible to figure out who actually died inside ; However, dead bodies were
being removed from the theater immediately after the all-clear was given, so an unknown number of people died in their seats before anyone could ever have a chance to get to them ; Dozens of survivors have been crippled by the gas, too, medical response or not. 64 people received compensation from the Russian government because of long-lasting health problems.
And despite that, it was
a great success, because 84% of the hostages survived ; But that doesn't mean gas use isn't risky. It was deployed despite the risks, not because it's a good go-to option in these sorts of situations. Just like it's usually not a very good approach to storm an airplane in the middle of a hostile country, but you might not have a choice.
In short: using highly potent gas stands a very high chance of doing little to the hostage-takers (who run on adrenaline, and often are young and healthy) while killing all the hostages except the young healthy males.
Yes, because in the only case it was tried on big scale that's exactly what happened. Oh, wait
It's not exactly
what happened, doesn't mean that's not a risk. People certainly did
die from gas poisoning inside the theatre. Therefore, using gas isn't anywhere near the proposed scenario where a CT team pops a can inside, everyone is knocked out, no casualties.Here
is an annex to an RTO report on non-lethal weapons dealing specifically with the use of non-lethal agents in the theatre siege.
It states in chapter M.6:
This counterterrorist action showed on the other hand that chemical “non-lethal” weapons are not always non-lethal. The variability of the situation (e.g., where one was located within the theatre) combined with the variable sensitivity of the population of individuals in the theatre (e.g., age, body size), combined with the disastrous consequences of failure, created a situation where non-lethality could not be guaranteed.
So...not a silver bullet solution to every problem. Not even close, because two out of three problems will always