@colourful_hippie: this is a show though. I'm not saying that doesn't happen or anything, but I don't think they'd put it there if they weren't trying to imply something; especially considering how much screen time they have.
Like, why would they have put that scene there if they were just trying to imply they were good friends? The very act of going on a spontanous multi week vacation to the spirit world would make me assume they were good friends anyway. That scene doesn't make sense to me if they're just friends.