I've been reading a lot of the theories and discussions online, and I know people tend to buy the theory that Orin sent the Entertainment. I understand the motivation, the fact that he was at the post office, a lot of the circumstantial evidence, etc. However, what I don't get is how Orin even had any of the knowledge that this requires.

Maybe he learned about the Entertainment from Joelle, but were they even still talking post-suicide? Joelle doubts that a lethal cartridge even exists, so it'd be weird for Orin to get that belief from her. Plus, he would have to be so convinced that the Entertainment is real that he'd go to his father's grave site, dig him up, and take a cartridge from inside his head. How can we explain Orin being so convinced about all of this that he'd actually go and do that?

I hope it doesn't seem like I am trying to object to the theory, or something. It actually seems like a really, really great theory, but the questions above have always been a stumbling block for me.