All JMO, but...
First of all, the difference between a rule and a law seems extremely relevant here. Breaking a law is criminal, and if the result of that law-breaking is someone's death--even if you didn't intend for that to happen-you're likely to be in criminal trouble. Failing to obey a safety regulation is negligent, and would be much less likely to result in criminal charges, I would think, though it can if the negligence is bad enough.
It isn't that actors are exempt from ordinary rules, which is why AB is likely civilly liable. It is that, contextually, it was a ton more reasonable for him to rely on the word and procedures of professionals who had been specifically hired for this purpose than it would be for the average person to accept his buddy's word.