Most of this stuff you are talking about is just fancy ways of saying "models". This is all en vitro science, not en vivo. There is a real barrier there, and without real, human testing all this humanized rats crap is just marketing. There is simply no way an RNA particle is going to circle the world, there is no actual science to support the idea, only Hollywood NLP.

DEFUSE is almost certainly a narrative prop and not a real plan--a huge red herring to convince people that "lab leak" is real.