My mate came up with a theory with one of your plotholes-
I guessing with the first plothole you mention-
He theories that the reason why you become a walker as soon as you died is because of your immune system which is what keeping you at bay from becoming a walker. As you died or get biten, your immune get weaker and weaker until it's gone therefore you become a walker.
I don't know maybe the amount of the virus in a person blood in different from one another since a dead/ biten person has different amount of time to become a walker. Maybe that sample that got decontamination was the perfect about of virus in it?
Maybe for the intended cure, it suppose to cure the right amount in a infected person but too much of it would be an overdose?
Maybe for the intended cure, it suppose to cure the right amount in a infected person but too much of it would be an overdose?