Japanese scientists did unorthodox and horrible tests on humans for the sake of science. This includes cooking living humans (which is how we now know how much water makes up the human body). The atrocities do not compare to nazi sciences (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4822534/) but the Japanese empire did horrible things to people for the sake of knowing. If you ask me, it wasn’t worth it. Look up Unit 731 real experiments and depictions. It will be very informative
Bruce Dickinson wrote a song about it: https://www.youtube.com/watch?v=yE-2IhIwvek&t=2