Well. Damn. This isn't what you expect to see. 

I am going to assume what you mean is fatal experimentation, since medical experimentation on human subjects is done fairly regularly through a multitude of studies. What you want is the ability to move away from western applicants who, you feel, are not willing to let you go as wild as you want to. 

Imma dive into the ethics part of ethics because I feel this has been neglected. The original premise seems to... more or less assume that poor people have failed to be human because they are poor. Somebody lives in the slums, and not only the slums but the slums of AFRICA! They must not want to live! I really doubt that most people who actually live these lives are seeking to die for a McDouble. These are people who have lives, even if they are troubled lives. They have families or friends, and they do more than stare wantonly at camera's while Sarah Mclachlan plays in the background. There is starvation and disease in these places, which are complex issues that were as a civilization are trying to fix, but just because hunger and disease is common doesn't mean that life in these places are composed of nothing but that.  

But lets say you do set up some sort of "St Mengele's Clinic for the Deconstruction of Wayward Poor Folk." And you do go about offering food for the opportunity to do what you want to do. Can you insure that they are informed? If you come up to somebody and say "I will give you a place to stay and some hot soup if, tomorrow, you come to my clinic and..." What you say next is important. Telling somebody the truth in clinical terms, "I will inject your lower urethra with a potent mixture of sulfur, charcoal, and potassium nitrate and we will test the effects when these conditions are subjected to rapid oxidization." This could be technically correct, but a person who is uneducated and is naturally inclined to associated doctors with healing could easily consent without knowing that what you just said was. "Imma explode your crotch so I can see what that is like."

So lets say your clinic introduces plain-language consent forms. You go up to these poor people you want to slice up and tell them straight-forwardly what you want to do. "I want to explode your crotch for science." Occasionally, the people you send to get applicants have their ass kicked by frightened poor folk (and the whole world applaudes). Maybe you get one or two sincerely suicidal people. This might look like a fair bargain - human-experimenting doctors get to Frankenstein some poor folk, and enough of these doctors go missing in the slums while seeking applicants so that we don't have to deal with all them returning to the west to haunt us here. But that's not the only problem.

How do you keep people from abducting their neighbors? Or consenting away their children? Sure, you can put in protections, but do you imagine a murder-hospital that doesn't have trouble bringing in patients? Can you ensure that your applicants have been given an option, and more importantly, WOULD your hospital ensure this in the first place? After all, looking the other way and accepting a dirty application would mean a person to experiment on, and it would mean more funding from whoever you managed to winkle money from. It is easy to approach this completely within the hypothetical and say "We will be completely honest" but you are already required to recruit people who do not see these applicants as entirely human, since empathy would necessarily make this sort of work impossible. You simply can't ensure that everything will be on the up and up. St Mengele's couldn't even operate without a decent amount of straight-forward murder.

So, to simplify. Your belief that being poor means that you have no reason to live is flawed. That makes the hospital flawed from its opening. Because applicants would be hard to find, dishonest means of collecting applicants would be necessary for this to continue. Since this hospital's very existence will depend on dishonesty, and because you could only use doctors who don't empathize with the poor, your hospital would by necessity become a murdering machine. 

This is the larger problem of ethics. If a perfect world where everybody who came to you for fatal experimentation of their own free will, and with a clear mind not addled by disease or mental disorder, fatal human experimentation could potentially be accepted. But because opening the way for this sort of experimentation inevitably opens the door for significant breaches on human rights, either through trickery or out right murder, fatal human experimentation cannot be allowed.

And if we are completely throwing human rights out the window in all cases where the needs of the many might outweigh the needs of the few, then I want to start a restaurant where we feed students of medical ethics who disagree with the concept of ethics to starving poor people.