A carmaker's claim to be the safest is mostly an artefact of comparing a new car against a fleet average twelve years old.

Any true safety improvement for Tesla is good to have, but is much more likely due to comparison against an "average" vehicle (12 years old in the US) which is much less safe than any recent high-end vehicle regardless of manufacturer, and probably not driven on roads as safe on average as where Teslas are more popular.