This is an important distinction which I believe was made to thread some legal loopholes. They all signed paperwork that they were participating in the "mission" as a crew member of an experimental vessel.

So literally, it is like, "the four of you's job is to look out this window, make sure it doesn't fog up, my job is to do everything else, alright let's dive"

That doesn't absolve them of negligence. A crew hardly signs up to be killed.

Recklessly killing your workers is even worse.

Many jobs are dangerous and regulated but killing customers is different. somehow it is the insurance companies that are the first line of defense when some conjures up a novel scheme.

Dangerous jobs still require the employer to try really hard to make them as safe as possible.

It doesn't sound like that was the case here.

This was out in the middle of sea not much jurisdiction. I think the crew would need a labor union and refuse to work to improve the working conditions. Consider the guy was on the sub I'm sure he did everything he could think of.