That is still improbable. It just doesn't make sense to have an arsenal of professional killers (Gin, Vodka, Chianti, Korn and etc) and I'm sure that these guys are paid big. Seems like the cost outweights the cause, if this is the case.
Well It could be that the effect of the drug was to completely de age the victim MIND and body. But its purpose is still for the same, to shut up those people who know to much by turning back them completely to their younger state. I just can't believe that the BO will try to make an Immortality drug or a drug to raise the dead. The latter seems to be too much, I mean what can the BO earn from creating a drug that raises the dead?
Yeah. And we have to remember that Ai isn't some kind of demonic entity who want to get what she wants. You'll see that she's caring to the people around her and She doesn't want to risk losing them or making them feel sad.