Bohdan Stashynsky's Gas Gun

Origin
Bohdan Stashynsky is the KGB assassin of Ukrainian nationalist leaders Lev Rebet and Stepan Bandera who were killed in the late 1950s. He used a spray gun that fired deadly cyanide gas from a broken capsule. Its intention was to make assassination appear as cardiac arrest, which worked until he defected to the west and explained the method.

Effects
Releases a lethal form of gas that induces cardiac arrest. Death is near instant for the subject. The handler will not be as strongly affected, allowing them time to swallow the accompanying antidote tablet and ampoules.