McVeigh did.
McVeigh did.
Essentially. But Francis Gary Powers didn't have a pill as his *just in case* way out, but instead carried a silver dollar bored with a hole containing a needle coated with a saxitoxin. [STX]
Powers did not use the needle and warned his captors to be careful in handling the silver dollar. The Russians pricked a dog with the needle and the dog died in ten seconds.