If an immoral act becomes a job it stays immoral whether or not someone is doing it because they were hired to do so, whether or not they were doing their jobs is irrelevant, it's not like they're poor mercenaries who all have tragic backstories like trying to pay for their mother's medical fees. Some of them probably justify what they do with some utilitarian thinking such as "a few people going through this to potentially help all of humanity in the future is a low price to pay". We can assume by the nature of their work that they're all extremely qualified people who could easily have found work somewhere else, probably. But i don't think Nagai even views it in terms of ethics and i don't think anyone in his situation would have either, indescribable pain is being inflicted on you and the only reasoning he can give is that his best friend would've hated him for it. He could've knocked them out, pushed them away or incapacitated them in other ways.>he understands the importance of keeping someone who studies Ajin alive, as they could help with the condition later on.
Yeah again we're not talking about him killing the scientists after his escape but during the experiments.>If he kills them in retaliation, he proves to society that he (and Ajin by association) are dangerous and need to be neutralized.
I think it's been fairly well established that Nagai is way too smart to end up with this conclusion, even if he did manage to escape the facility without killing anyone he probably should've been thinking "it would all either covered up or faked by saying i killed everyone but if i don't do anything i'm going to be stuck here forever".