Maybe we can do a meta-Milgram. A group of junior researchers are tasked with implementing what they believe to be a Milgram experiment, and while performing it the subjects (actually actors) start faking psychological distress in response to having to shock the completely fake learner subjects.

One of the researchers feels guilty from the apparent panic attack his subject appears to be going through, so he excuses himself from the experimental room and approaches the lead investigator who's watching on CCTV from outside:

“Professor, this subject is really suffering from their belief that they are electrocuting the learner. I believe this is unethical, can we stop please?”

The professor replies:

“The experiment requires that you continue.”