barsantos where they don't even realize they are together
like Al Hashimi had a hard time integrating with Robby around, so when after the next few shifts when he's gone, she invites the Pitt staff out to dinner with her. it's just meant to be so she can get to know them better, so she can work well with them.
now they agree the first few times but most of them have other things going on, so inevitability it becomes just santos and Whitaker because they don't have much to do outside of work and like free food. then it becomes just trinity and Baran because Dennis feels like he's third wheeling whenever they go out.
then it becomes sleepovers because they stayed out pretty late, lost track of time, and obviously Baran isn't going to make her drive home alone at 12 am. then they hang out on their days off, because Baran's son invited santos to his soccer games, and before they realize it they've practically moved in together.
now trinity is still "casual" with Garcia but she's getting more and more agitated every time santos brings up Al Hashimi and she's wondering why, like she's just her coworker/ supervisor, and this really shouldn't impact Garcia at all? and anyways in the middle of a big argument Garcia ends up saying "if you really don't want me go back to dr. Al!" and that's when trinity realizes how romantic their interactions could be seen.