I'm not sure that this virus even behaves in this way where a BSL-4 worker could become infected. What we know now is that you need a concentration of virus particles over time in order to come down with the disease (in other words, you are most likely to catch it drinking in your friends living room for 4 hours with an infected person, than in a grocery store where an infected person might cough on you in line but there is no long term exposure). I can't imagine where there is a situation in a lab environment where you would have the equivalent of an infected person drinking beer with you for hours in terms of exposure. Even a rip in your PPE wouldn't expose you to very much particulate compared with an infected person spitting in your face conversationally for hours.
>>asdff+(OP)
That's a good point. I have a hard time as well believing anyone who was even coming close to following BSL-4 protocols would get infected with this.