2002 Nord-Ost Siege 

An infamous event where a terrorist group took over 800 hostages in a Russian theater. Russian officers responded to this crisis by pumping opioid gas into the poorly ventilated theater, causing every single hostage and terrorist to fall unconscious. Spetsnaz officers then went into the building, shot the terrorists while paramedics tried to retrieve the hostages.

Out of the 800+ hostages 170~ hostages died, all of which were due to suffocation unrelated to opioid overdose. Who would have thought that stacking a bunch of unconscious people on top of each other was bad?

My favorite Russian event was the 2002 Nord-Ost Siege

2002 Nord-Ost Siege by Lord Pringlett March 9, 2020