I never got Willis
being a security guard. "You like helping people" Glass tells him. Security guards don't really help people. Oh, sure, on occasion, but probably not more often than any other bystander.
Why not make him a paramedic, EMT, volunteer firefighter ... something more along those lines.
Granted, the script emphasized what a regular Joe he was, but then being a first responder, especially in a volunteer setting, isn't exactly the height of glamour, & certainly wouldn't have made him wealthy.
Writing this after having seen "Split". Have to agree, it's a move in a better direction for Shyamalan, & probably an argument in favor of permitting filmmakers that seem on an irreversible downward slide helm yet another major production.
I don't love either film. But I find it amusing that both suckered me into superhero/villain type comix genre pictures, which I normally avoid.
Still, wrt Unbreakable, I'm bothered by protagonist's line of work. I think it would have been a much stronger film if he'd been in an actual helping line of work--even if circumstances mandated he remain on the lowest rung of the professional ladder.