[He doesn't want to tell Al. Ed makes it a point to fixate his gaze somewhere off in the middle distance, maybe the floor, but pointedly not at his brother for a moment while his mouth turns into a firm frown.]

...It was some kind of warning, Al. I think it has to do with all of this. [as he says "this" Ed waves his hands in front of his glowing eyes.]

I don't think the things you saw in your vision were bugs, Al.