I watched the entire series and understood the reasons why Franco became Lieutenant at the conclusion of the series, but I always imagined what the conversation would have been like between Tommy & Franco before hand considering Needles had made it a point to claim Tommy was acting Lieutenant early in the final episode. Here is what I came up with.
Tommy Gavin wasn't the kind of guy to ride roller coasters, but the past week of his life was the biggest since that fateful September morning. On the one hand, he witnessed the marriage of his first-born child Colleen to a firefighter within his own crew, then reaffirmed his own marriage vows to his wife Janet on the very same day. Two nights later however, his world came crashing down during an arson fire at a vacant warehouse. His best friend, closest confidant since 9-11, blah, blah, blah Lieutenant Kenny "Lou" Shea tragically did not make it out alive. Tommy & Lou were not blood related, but Tommy treated him like family in the same manner he treated his cousin Jimmy and brother Johnny, and now all of them were gone.
Lou's death was also God's way of bringing his new son into the world, born the afternoon of Lou's memorial 5 days later, Shea Gavin. Despite the fact he fainted upon coaching his wife through the delivery on the fly in his house (FYI I wasn't sure if his living arrangement was an apartment or a house in the final seasons), Tommy was on as Cloud 9 as a Gavin could be while riding the ambulance with his wife to the hospital. However, Janet had mentioned that she encouraged Tommy to return to the firehouse & keep doing his job instead of retiring or moving to an administrative/training role (I could see Tommy acting as a Probie School Instructor) and he was content on returning to 62 Truck as Lou had wanted it in the letter Tommy read at the memorial service.
Even without Lou, the crew was still a rock-solid group, sure losing Lou was a setback, but it could be overcome, but Tommy knew he couldn't fill Lou's shoes as Lieutenant. He wasn't so much afraid of the paperwork required, but Lou always knew where to put guys during a job and Tommy was afraid of making that kind of mistake. His mind went to Franco, who switched jobs with Lou as a bet not too long ago, and despite a foul up on a water rescue, Tommy also saw how Franco ran the house and reorganized everything from the lockers to the kitchen and believed he would develop to a fine lieutenant. The only question was Franco willing to take Lou's position in 62 Truck or start fresh somewhere else in the FDNY.
Janet's hospital room was full of activity while she was monitored between Colleen, his other daughter Katy, new son-in-law "Black Shawn" (his name given in the credits was Bart), Teddy, Mickey, Shelia, and Maggie. After some time, the rest of the fire crew came to visit and after a whirlwind of congratulations and fuss over the new baby boy, Franco had asked Tommy to talk privately.
(T is for Tommy dialogue, F is Franco dialogue):
F: Granted Needles and Black Shawn are there for backup, but I wouldn't let Mike or Sean out my sight if that was my kid, so here it goes. (He hands Tommy a envelope addressed to him and Tommy immediately recognizes the handwriting)
T: Lou wrote you a letter too?
F: Yeah, it wasn't in my locker like yours, but Needles had it in his office. (Tommy starts to read the letter as Franco talks). I know I screwed up big on that water rescue call, but I'm flabbergasted that Lou has this much confidence in me in running my own house one day after that. (Tommy can tell Lou wrote this after the water rescue call) I'm gonna be working under Feinberg downtown starting next week, you think I'm ready for a blue shirt full time?
T: (Processes what Lou wrote) We've been through some crazy *stuff* (I know what he would say but to keep the rating kosher) without reopening all those old wounds, but after 14 years together (documented evidence from Season 3 finale that Franco was a probie as Katy was born which was before 9-11 and series ended in line with the 10th anniversary so I'm just estimating), if Lou didn't feel you were ready to be a lieutenant or a chief one day, then why would you still be here? You're gonna make a great Lieutenant, but how would you feel about wearing that blue shirt at 62 Truck?
F: (Tries to fight what he knows Tommy is about to say) T, I appre-
T: Look, Lou wants this, he wouldn't have written letters to each of us if he expected we both go our separate ways after he died which keep in mind he wouldn't have expected a week after he wrote these, don't you think? Look, me being Lieutenant is going to be hard enough on my own, but now ordering my son-in-law around on calls? I respect the hell out of the guy, but something goes wrong with him on the job, I wouldn't be able to look Colleen in the eye. I live for being the crazy-hero guy of this group, there's no one else in the department I would want to succeed Lou as Lieutenant of the crew I work with.
F: You do make a good point, but still, I don't know? I'd feel like if I screw up again, I would not be honoring Lou in the way he deserves to be remembered.
T: Do you remember the restaurant fire the New Year's Holiday about 8 years ago?
F: Vaguely.
T: It was one of Lou's first calls since his promotion, he pointed Billy (old guy from the 1st season) to a room where smoke was billowing fast even though Billy knew that would be a mistake seeing he was this all-knowing firefighter. A few minutes later, Lou went towards that direction and nearly fell through a crack in the floor and almost died that night.
F: Wow, I did not know that, I was on a upper floor doing a sweep with Sean.
T: Yeah, Lou didn't want to make a big deal out of it and Jerry covered for him, but we got back afterwards I saw him in his office, he threw some stuff on the floor, then he saw me and closed the door. (Seeing Franco now understands) The point is he never made that mistake again, just like you won't make the same mistake when we get another barge call. So, how about it Lt. Rivera? (Offers a Handshake)
F: You what this means right? You gotta me call that every day, no more slide slips Firefighter Gavin until you do retire. (Moving right back into Lt. mode) AND A FIREFIGHTER DOES NOT OFFER A HANDSHAKE TO A SUPERIOR OFFICER!
Tommy gets the point and offers a salute at attention which Franco returns, then Franco gives Tommy a casual handshake to seal the deal.
F: Let's go back to Janet's room and talk to Needles before Dumb & Dumber rot your son's brain, ok?
Thinking of doing more one-offs from shows/movies I like from my life and Rescue Me was one of my favorite shows.