Spoiler - Hero in the Hold Casting Sides 

Wow! I'm confused. Is Teddy a ghost?

Yeah, I think so. That's why I think that this episode may be the fantasy one, 'cos Booth is fantasising that his old war buddy is with him.

I don't think it's the fantasy episode. It's just Booth hallucinating because well he's been kidnapped and trapped in a sumbarine thingy. I'd probaly see someone who wasn't there in that situation too, although in my case it would probaly be my grandpa.