Speculation: Gregory didnt mean to shatter Roxy

While he tried to crush Chica and Monty on porpuse, she jumped in front of the racetrack by herself. and gregory tried to drive away from her in the go-kart, heading in the opposite direction, but Gregory ended up falling out of the kart and hitting her.

"So what was his plan to get her eyes?" I have no idea. But it's not a smart plan to assume she would throw herself in front of the go-kart to catch him...