Kho seems like a much better student than I am. This is final exam season for most of us, so my instinct is that Kho just retreated out into the woods for a massive study marathon. And that he had to do it cold turkey, otherwise we'd pull him back in with all the memes and distract him.

Of course, this theory about Kho retreating into the woods doesn't preclude the ever real possibility of him having been eaten by a bear.