When you work in the industry writing software which can kill people, it is not so difficult to raise up your voice and say no when it could threaten life of people. Even if you are wrong it is still useful to raise your concern, as this would trigger an in depth analysis. I would say that it is even easier when your company experienced deaths due to products they make.

But.. I am not in the position of being responsible for signing the design which makes my life easier. If an accident happens I have my conscience for myself and proof that I objected.

However, it is much more difficult to gain attention when you cry foul to something unethical being done (diesel gate comes to mind here), even though it can remotely leads to deaths.