I just watched this episode for the first time in a while. Am I the only one who has less of a problem with using medical knowledge that was gained unethically, and more of a problem that those aliens probably do the same thing to other crews they come across? I guess the argument is, if you use medical research that was obtained brutally, you encourage brutal research to be done in the future. But if that's the argument the outcome was a little bit hypocritical. They used the research as much as they needed for their own ends then threw it out and felt good about themselves. Isn't that kind of like riding around in a private jet then saying 'For shame' to people who drive hummers? Do other people than B'elana have to die so we can morally square our actions with our beliefs? Would the crew have even cared if the hologram was a Vulcan who just happened to have studied the Cardassian's research?