To me, it looked like he took it upon himself to slide across the goal line...of course, I wasn't the one carrying the ball and running towards the endzone, and I don't know what was going through his mind for intent.
My point was, if it was intentional, he doesn't need to risk it. I found from a quick search about the NCAA slide rule, which was changed after the infamous Kenny Pickett fake slide in the ACC Championship:
The NCAA is now enforcing new rules against fake quarterback slides after Pittsburgh quarterback Kenny Pickett's controversial touchdown run in the ACC Championship Game last Saturday.
foxsportsradio.iheart.com
"Any time a ball carrier begins, simulates, or fakes a feet-first slide, the ball should be declared dead by the on-field officials at that point," the memo states. "The intent of the rule is player safety, and the objective is to give a ball carrier an option to end the play by sliding feet first and to avoid contact. To allow the ball carrier to fake a slide would compromise the defense that is being instructed to let up when the ball carrier slides feet first."
So had the ref viewed the slide by the rule above, Leary could have been ruled down at the spot where he began the slide...which would have been before he crossed the goal line. Obviously, it was subject to the ref's POV, so it's always better to not leave it up to interpretation.