It creates a barrier to prevent supernatural things from coming in - ghosts and shit. Can't tell you how many times salt's saved my life -- not that it matters anymore.

[ Alex is talking as he goes, splashing holy water here and there in the room. He's not thinking about the words coming out of his mouth. Jaime seems to be doing a good job. ]

I'll do whatever I can to save him, but I can't do much until I get a look at what's haunting him.