This was the only reason I could think of for why two characters as great as Lucius and Alfred would stick around. It should be obvious but this is a character study, of Alfred. I do not own any of these characters, I do not make money off of doing this. The only thing I' getting out of this is pure unadulterated creative enjoyment and less hours for me to spend doing my real work.
The Reasons Not Fully Given
Night is quite possibly the busiest time for Wayne Manor; a fact not lessened any by the owner of the said manor house never being in. Most people sleep at night and Alfred can remember a time when this was true for him as well, but these days he takes what little rest he can in the afternoons, or early morning. These days he stays up at nights, making plans, plotting plots, doing paperwork and making sure the surgical equipment is ready for his master's usually slightly mangled and bloody arrival back home.
Lucius Fox is there more then he isn't, and tonight they've spread the latest plans to renovate the car, everyone, but Bruce, calls the bat-mobile, across the dinning room table. They had spent an enjoyable forty minutes arguing over how best to redesign the motor so it'll do double the speed without over heating and blowing up. Somewhere along the way Lucius had taken off the blazer he'd come straight from work still wearing and rolled up the sleeves of his shirt. Now he runs his fingers through his hair and scribbles something down on one of the notepads spread across the table. Alfred stretches trying to get the kinks out of his back and wonders not for the first time what Bruce would have done if he'd majored in say Classics like he'd wanted to instead of Astrophysics and Engineering like he'd actually ended up doing. He wonders what Bruce would have done if either he or Lucius, or for that matter the hundreds of scientists and engineers, had ever said no to any of his plans and schemes. Money can only buy loyalty to a point, and he and Bruce had crossed that line a long time ago. Still there is much to be said for a quiet life; on the other hand a quiet life in Gotham was similar to a quiet life in Hell.
Lucius is still scribbling on the pad of paper, reaching absent-mindedly for his laptop, frowning to himself. They'll be at this all night Alfred knows. Sometime near morning Bruce will drag himself home and Alfred will stitch him up, ply him with morphine and tea, and if it's a good night manage to get him to go to bed for a few hours at least. Alfred and Lucius might not sleep at all but they will figure out how to re-engineer the motor and Bruce will only ask if it's done yet not even caring how long it took them, how much of their lives they don't live because of him. Alfred knows this because this is hardly the first night, and it won't be the last.
" I think a spot of tea would do nicely"
He says and stands, Lucius nods and smiles up at him briefly before going back to his laptop. Alfred smiles too and comes to stand behind Lucius chair reading equations over the top of his head, one hand on the other man's shoulder. Lucius' hand comes up to cover his own and Alfred smiles again fondly.
Once Bruce had told him rather accusingly that if Alfred had a life outside of Bruce's own personal crusade Alfred might consider taking a day off or possibly two. Alfred had thought at the time the remark was incredibly naive, and unobservant of Bruce but then Bruce had never been good at seeing things that weren't blatantly obvious, and a harder time still seeing things that did not have to do with the Batman.
Outside of the high windows of the manor house, the world goes to hell in a hand-basket, and the Batman fights on, for everything that should have been, and everything the citizens of Gotham might want and not realize yet. Inside Alfred leans over to kiss his man and then goes to make them some tea.