Finally character development in this episode between Rigsby and Grace! Cho being the person Rigsby trusts the most comments "Dude you need counselling" when Rigsby keeps getting distracted over Grace potentially meeting people at a soup kitchen. It does seem rather farfetched to feel threatened like this and shows Rigsby being a fool in love even before he faces Grace to say this leaving her speechless.
Cho himself seems to be picking up Jane's unorthodox methods by overbluffing a suspect into telling him what he knew. He has the get it done attitude and goes around Lisbon because he trusts Jane (more than Lisbon?) which has in the past gotten him in trouble. Raising the question how far would Cho trust Jane? It is clear that he doesn't always understand why Jane asks him to do stuff so would he trust Jane to not kill Red John? Lisbon clearly doesn't. As one of the more drier and serious characters you don't expect much from him but that's why it's easiest for him to surpise us.
Overall this was an average episode with Jane homing in on the most likely motivation for the murder at the "haunted" house and doing his usual thing of setting up the bait for the hidden fortune with Lisbon. Whilst it distracted away from the main Jane Red John obsession it didn't feel too much like a filler with Rigsby at long last plucking up the courage to confront Grace about his feelings and Jane having his fun at the expense of almost everyone he meets. Actually in this episode Jane doesn't meet that many of the suspects and has almost no face time with the killer till the end which is a bit unusual so the focus was mainly moving Rigsby and Grace closer together.
Rigsby being a terrible person to hide a secret probably set off Jane's warning bells at the end that the two were finally together leaving only Lisbon in the dark. It should be interesting to see whether Lisbon would have a problem with them when she finds out. After the episode "Red John's Friends" it seems pretty clear that the team will stick together through almost losing their jobs so my bet is that Lisbon would tolerate it as much as she can tolerate Jane's antics.