And after falling sick from contact with the deadliest nerve agent known to man, they have made a full recovery.
It's not the deadliest nerve agent known to man.
And you don't want it to work instantly, that would make it difficult for the person who planted it to make their escape.
An example would be the Ricin attacks made by Soviet bloc agents during the Cold War.
Well, the reports did say that Novichok is 5 to 10 times stronger than VX, which is what the North Koreans used on Kim’s half brother, at the Malaysian airport. He died soon after.
Haven’t seen any reports that Novichok induces a delayed reaction. Do you have any?