Villains in Halo have always had tendancy of giving epic monologues, and using excellent and vague disction. I think the Didact is the best example thus far in Halo. One of my favorite lines he says is.
> You have not been Composed. Such inoculation should not have been possible
Originally, I thought that inoculation meant: An incredible feat. This made sense in context, so assumed it was so. I doubted this was the correct definition, so I searched it up the definition here.
This is what it says:
> the act or process or an instance of inoculating; especially : the introduction of a pathogen or antigen into a living organism to stimulate the production of antibodies
I was quite surprised as to have come across this. And even more surprised at what it could mean for the Composer. I see this leading to two possibilities (the first being the most likely):
The Composer itself uses organic means to convert a living organism into digital data. In order for it to behave in this way, it would mean the Composer is a synthesis of organic and the digital. How this could work, is that the energy beam, or the energy wave, utilizes the energy to behave almost like a pathogen, or virus, to digitize biological information.
This could also explain why the Didact becomes immune to the Composer when trying to make himself immune to the Flood. He changed his biology in order to make it so his cells cannot be attacked by a virus, or pathogen. The side effect from this made it so his cells cannot be attacked by the “Energy Virus” If this is the truth, the implications from this make the Flood so incredibly complex, that they are beyond the understanding of Tier 1 and below species.
As we know, Forerunners undergo Mutations in order to achieve a higher social status in their rate. it is possible that a Mutation is achieved through the use of a synthetic virus to transfer genetic material. The Didact could then be reffering to the fact that the Librarian figured out a way to transfer Forerunner DNA via a “Mutation Virus” without visually affecting John.