Here’s another LOST theory I’ve been thinking about.
Hanso and the DeGroots start working together, Hanso for some other
reason than he’s not telling the DeGroots. He finances the
construction of the hatches on the island so they can be used as
observation posts for the “perfect society” ideas the DeGroots have.
The observers keep in the hatch, saying they’re just going to observe
what’s going on.
The experiment starts, only to have everything go completely berserk
once the people on the island itself figure out they’re victims of
whatever Hanso had planned. Maybe he found out about the black
smoke, and wants to weaponize it, or something like that. The
people in the hatch take injections so that they can’t be taken over
by whatever Danielle was referring to. I remember her saying
something about not wanting whatever happened to the rest of her group
getting loose in the “real world” if they were ever rescued.
(Possibly, “infected” by the black smoke?)
The Others have figured out they have some kind of defense using
people that the black smoke won’t mess around with, and that’s why
they’re grabbing people.