Best I can do is Robby trying to have a new golden boy but doesn't manage to be friendly enough, Dennis always acts as if he's a deer in headlights whenever Robby asks him if he's sure about a plan (Robby who's used to people who say things surely so when Dennis asks him he's like "are you asking or telling me?" Dennis takes it badly, like assuming he's done something wrong so he needs to be supervised more?) so when Frank comes back IT'S AWFUL how quickly Dennis becomes Frank's shadow. Like Robby sending Frank to triage and Dennis following along asking some questions about some medschool coursework he's been stuck on and Frank's yapping away until he's telling Dennis he'll take him to get a bite to eat, if Dennis manages to clear more people than him in the first hour or something. "Ik med students get paid nothing, come on"
The chaos of Frank bringing up podcasts or weird cases he's seen or asking v dubious ethical moral dilemmas over some patient who's cracked open on the table and Frank's pressing Dennis like "What would you do, hypothetically though?" and if this patient lives (he does) he's going to give the worst patient satisfaction score this hospital has ever seen but it made Dennis laugh.
Frank def thought in rehab that he's going to be Dennis' biggest hater but the concept of Dennis getting addiction because he used to be homeless and def came across a lot of addiction issues has my whole heart. Esp if the reason they start getting along is because Dennis notices Frank's scrubs kind of look slept in, he can tell Frank's been sleeping in his car or something and that's why they become pals?