Oblivious to his greater presence or not, the fact that Aerith had looked around with some uncertainty was not lost upon him. It spoke to a time before the short period he had been acquainted with her. Of a life spent on a short leash, tethered deep within a sectioned off, numbered, polluted scrapheap underneath Midgar- constantly watched.

He should have backed off. While it had been a (startlingly) great number of years since Vincent had worked for his previous employer, Instinct was something that never faded. That instinct told him that his target was wary. That further persuit would be pointless.

...But Aerith wasn't a target. Anything but. "Acquaintance of a short period" or not, posthumous understanding and gratitude for her or not, she was important. So he continues to persue while keeping her at the absolute edge of his vision- only speaking when he became certain that she appeared to be leaving the city.

"Aerith."

A simple statement. Just her name.
... Whether she'd recognize him or not.