There is a difference between getting a few virus particles on the street from another person or getting bucket loads full while operating in that environment.
In the former case your body gets some time to respond, in the latter case the reproduction speed of the virus will surprise the defense mechanism of the body.
Medical workers from low too high are the real heroes at this moment in this pandemic.
Have they confirmed that exposure to a greater number of particles leads to greater symptoms? Last I heard that was still unclear