Forgive me if this has already been discussed. I look through some threads and couldn't find anything that jumps out at me.

I've been thinking that Charlie was getting sick based on the look of him last night. But then Locke was acting all weird, especially when he nailed Charlie in the face not once but three times. After the first shot most people would have stopped.

What if the sickness doesn't kill you but drives you to kill other people?

Could Locke be getting the illness? There may even be some link to him being cured of his paralysis and then being the first one to succumb to the illness (think Flowers for Algernon as an odd allegory).

Rolly Sig Shop