Wow Fukumoto managed to give me a good laugh two chapters in a row! Couldn't hold it when Ishitaka found Kaiji in the park!
That being said, that's a bit too much for someone who gets the bad idea based on some assumptions without any proofs.. at this point Ishitaka should take some medication as he's dangerously unstable.
Also, this situation seems too forced for being a starting point for the next plot, anything more plausible to advance the story could've happened instead.
Where is Kasuya