What do you think Mel wants their first kiss to be? What do you think Frank wants it to be? What does it end up being?
these are very fun questions, and i have been chewing on them for a few hours without feeling convinced by my own ideas. i think i would probably answer this very differently depending on the day and what i had most recently been working on! but here goes:
mel: i'm very partial to thinking that mel would have a crush on frank that she assumes is not going anywhere, which can either be a fun thing or a very sad thing, and i tend to think she would feel bad about thinking too hard about him like that and would mostly try to shut it down. BUT i can see her having a version of him that she thinks about almost as a fictional character, disconnected from her real friend/colleague Dr. Langdon. so i don't think she would be very practical or realistic about it, since it's just a fun thought experiment haha lol not in this life amirite! so bring on silly and absurd romance book kisses: underwater! in the rain! at a ball! upside down spider man kiss!
(some personal favorite fic interpretations along these lines are If you're ready (I need you) by @annaandtheicecream and detect my sudden existence on your sonar by @queenofattolia)
frank: i similarly think that he would feel like a Terrible Person for thinking of his wonderful amazing too good for this world friend mel like this (not in an infantilizing way, but in a why do i ruin everything kind of way). however. i think he might have a twitchy imagination where he doesn't have very in-depth dreams/fantasies, but more like flashes of images he jumps between, and he starts having almost intrusive thoughts about places they could make out. ambulance bay. stairs. his car. her car. any vertical surface he could crowd her against. even though he doesn't entertain the thoughts, he knows it would be hot.
it ends up: that he can't stop himself from kissing her one day. he's dropping her off after they did something together, and he feels like she might actually feel the same, since she keeps smiling at him in this how is this real way. so he leans over the gearshift and kisses her, just a firm press of lips. she squeaks. he starts panicking when she doesn't respond in any other way, so he slowly backs away, heart in his throat, already beating himself up, and she is frozen, staring at him with enormous eyes. "why did you do that??" she asks him, higher pitched than he's ever heard, and how do you answer that?? he can't think of anything smooth to say so he blurts out "because I couldn't stop picturing it" and then she's like ??? that's what i do with my Imaginary Frank have i accidentally manifested him??
they sit there for a long, long moment before she slowly opens the door and exits the car, and they both want to say something, but neither of them know what to say, so she goes inside and he goes to lie on his floor and mourn the end of the best adult friendship he's ever had. but an hour or two later, she knocks on his door, and he thinks she's there to yell at him or tell him she's reported him to HR or something, but she prepared a list of questions for him, which they go through (do you have feelings for me? why? when did you realize? what is your ideal outcome of this situation?) and he's waiting for the other shoe to drop, but he answers best he can. when they've gone through all of them, she folds up the list, nods, and launches herself at him. that time it goes more like how they both thought it would :)