I don't own Agents of SHIELD and never will. No copyright infringement intended.
One of the many reasons Fitz fell in love with Mack is because the mechanic was one of the few who treated him normally during his darkest days, when he was at his lowest point after everything that happened. And right now, years later? He's the happiest he's been in a long time. He's still dealing with the brain damage and will have to live with it for the rest of his life but Fitz has come a long way and massively improved since then. And he loves watching his boyfriend work on cars (something he'll never admit but everyone knows anyway).
Mack turns around and smiles when he sees his boyfriend trying to pretend he wasn't watching. "What are you doing back there, Fitz?"
He shrugs. "I wasn't doing anything!" he tries.
"You can admire the goods any time you want, babe." And then Mack winks and Fitz starts laughing.
And then Grant shows up out of nowhere. "What are you doing?" he questions. He's bored since Skye is out on a mission with Jemma, Bobbi, and May. He misses his wife so much he can't even sleep without her in their bed so he's going to bother Fitz, Mack, Trip, and Lance (wherever those two disappeared to, anyway).
"Are you lonely?" Mack isn't surprised. Grant is always like this when there are few people he trusts on base. When Skye's gone? He's ten times worse.
"Nope." He hopes they bought it and frowns when they definitely don't.
"We'll get some … take-out … and watch a movie. Sound fun?" Fitz is hopeful he'll be able to lift him out of his funk that way. Normally he's the only one who can when Grant's like this.
The three of them run into Trip and Lance making out in the kitchen on the way to the living room. "Really, guys? People eat here," Mack complains.
"We caught Skye and Ward fucking on the floor and nobody said anything then!" Lance protests. That had been hilarious, though, something he's not about to admit right now. He's not stupid.
Trip starts shaking with laughter and covers his face with Lance's back in the dim hope that nobody has noticed. "All of you are morons. I can't believe we all manage to work with each other and not kill anybody."
Grant agrees with him. "He has a point. And we're still sorry you guys caught us in the kitchen, anyway. We thought we locked the door." He and Skye forgot but nobody has called them out on it yet so he figures they're in the free and clear. Hopefully, at least.
Trip stares at him. "You keep telling yourself that."
"We live in a place full of spies! You picked the lock! I know you did." And with that, the five of them head off to the living room in the middle of an argument they've already had dozens of times.
Fitz clutches Mack's hand while Lance literally sits down on Trip's lap. Grant stares at the two couples mournfully. "You know how uncomfortable this is, right?" Trip asks his boyfriend.
"I'll get up when you tell me to, Trip. But you didn't ask so I'm staying!" Lance starts laughing when Trip literally playfully pushes him off his lap.
"Hey, you wouldn't move." He shrugs and kisses his boyfriend when Lance stands back up and sits down next to him.
"I'll get you back for this later," Lance whispers. He has to plans to fuck Trip senseless later – it'll get him back for this (it's not logical but it works for them both for now).
Fitz looks up at Mack and yawns. "You need to work on vehicles more … often." It took him a few seconds to come up with the word he needed because he's exhausted and they can all tell.
Grant bites his lip and tries to push away the guilt. He'll never understand why the team forgave him but he'll always be grateful they gave him a second chance. "I'm sorry," he apologizes.
Fitz glances in his direction. "Grant, stop. You don't have to keep apologizing."
The five of them eventually decide what movie to watch, and Fitz is the first to fall asleep. Mack joins him less than a half an hour later. Trip and Lance disappear fifteen minutes after that with the excuse that they're tired (Grant doesn't buy it). He grabs a blanket and places it over the two men then heads to bed himself to finish the book he started a few days ago.
The next morning is a bad day for Fitz. He can't remember any of the specs he needs for the device he's creating and is taking out his frustrations on everyone around him. "Not helping!" he shouts at one of the scientists who scurries away. He's not surprised when Mack shows up less than five minutes.
"Lena told me you're not having an easy time of it today. You want to take a break and get something to eat?"
"No! I just want to figure out what the fuck I was doing! Get out!" Fitz doesn't mean it and they both know it but Mack is still furious.
He crosses his arms. "I don't care how frustrated you are, you don't talk to me like that. And you have several people you need to apologize to once you're done."
"Don't treat me like this!"
"Like what?" Mack questions, unfolding his arms.
"Like a child. What the fuck … am I thinking about? It's a small kid." Damn it, Fitz is even more pissed now.
"I'm not treating you like a baby, Fitz. But you need to leave the lab for a little while and cool down. It's the best idea for everyone right now." He hates when Fitz gets like this (so does everyone else). It's hard to help him when he's stuck in this headspace.
"Fuck you!" Fitz snarls but he walks away anyway and heads to the kitchen to grab something to eat. By the time he's done, he's calmed down considerably. "I'm sorry," he apologizes to his boyfriend once he sees him again.
"You're forgiven. I'm sorry if I treated you like a child. I know you're capable of doing anything you set your mind to but it doesn't come so easily anymore. And that's okay. We're all here to help you. And I'm always going to be there for you, Fitz." Mack grins.
And he does feel a lot better after he hears those words. As long as Fitz has this man by his side, he can grab onto his faith and build on it.