How is Zane in equilibrium in this scene?

How can Zane stop moving unless he’s directly under Vin? But if that’s the case, how does she get thrown backwards and not upwards?

The two stood opposite one another for a few silent moments. Zane had to know of her questions, but he offered no introduction, greeting, or explanation. Eventually, he reached into a pocket and pulled out a coin. He tossed it to the street between them, and it bounced—metal ringing against stone—and came to a stop. He jumped into the air. Vin did likewise, both Pushing against the coin. Their separate weights nearly canceled each other out, and they shot up and back, like the two arms of a "V." Zane spun, throwing a coin behind him. It slammed against the side of a building and he Pushed, throwing himself toward Vin. Suddenly, she felt a force slam against her coin pouch, threatening to toss her back down to the ground. What is the game tonight, Zane? she thought even as she yanked the tie on her pouch, dropping it free from her belt. She Pushed against it, and it shot downward, forced by her weight. When it hit the ground, Vin had the better upward force: she was Pushing against the pouch from directly above, while Zane was only pushing from the side. Vin lurched upward, streaking past Zane in the cool night air, then threw her weight against the coins in his own pocket. Zane began to drop. However, he grabbed the coins—keeping them from ripping free—and Pushed down on her pouch. He froze in the air—Vin Pushing him from above, his own Push forcing him upward. And, because he stopped, Vin’s Push suddenly threw her backward.