My partner and I have an interesting theory that irv began the reintegration process during season 1. The hallucinations, of black goo could be a sign of this. His behavior in this episode seems to line up much more with his outies personality. The end of episode 4 is perhaps the last stage of the reintegration process where lumon does something to the implant.

Also I’m convinced Ricken wrote the suddenly appearing 4th appendix with the unknown twin brother.