The Missing Homeless people were eventually discovered.

It appeared that the missing scientists from Midway University who worked on the Artificial Blood Substitute programme (which was eventually abandoned due to discrepencies in the results, a fatal attack, attempted theft and accusations of credit stealing) were paying homeless people to come to a warehouse. 

There they were training and testing the people who volounteered getting them to perform basic scientific experiments. The ones that they found were about basic high-school level experiments.

However before any more could be learned, a group of people in black vans abducted the majority of the participants and let the recently recruited homeless people go.

Exploring the warehouse they found bunks for sleeping in, a small kitchen area, lots of expeirmental work stations and in the basement a much more complex medical area stocked with plenty of the blood substitute.