Whats an unethical or dangerous experiment that you would like to see performed or perform (if it werent for the ethics/danger)
For me "How long could I get away with driving like an ABSOLUTE ASSHOLE all the time before I lost my licence or had an accident." Speed limits, red lights, stop signs... forget them all. Every day I have to drive sensibly and obey the law because without my licence I dont have a job, and every day I see at least one person driving like an absolute moron and I wonder...
I want to see how far you can push performance of the human body, and make the results compete against each other. All the bonkers whacky surgeries you can think of: limb lengthening, bone strengthening, replace their organs with bigger, stronger versions.
All the drugs: hgh, steroids, any performance enhancing substance you can pump into an athlete.
Have sports scientists raise children so that they're born into a dedicated training regime for running or swimming.
Then make them compete against each other in the trans-human olympics. I want to see someone do the 100m in 3 seconds, I want to see someone not have to come up for air during the freestyle, I want someone to throw a javelin 2 miles, I want bioengineered mutants doing gymnastics routines
Unit 731 was garbage science. About the only thing worthwhile that came from that was learning how better to treat hypothermia. Most of their experiments boiled down to "If we do terrible things to people, how much will they suffer?" with the answer being "A lot."
It doesn't take live experiments to learn things like surgery without anesthesia is less effective, or that not treating people infected with horrible diseases causes them to die in agony.