He didn't manage to restrain Prime from landing his blow on Kara, but he still went ahead and landed his own hit anyway. Pulling back to a hover, he watched as Prime was hurled into the street below, then allowed for his blue eyes to flicker off toward Kara. She had recovered. Unfortunately, she seemed more than eager to attack Prime. And Prime himself seemed just as eager to retaliate.
Superman was hoping to make an attempt at reasoning with the alternate version of himself. There had to be some level of good left inside of him, right? There had to be something there.
However, that didn't excuse Prime for acting like Bizarro or even Zod himself. At the sight of the innocents being thrown like ragdolls, Superman hurried forward and snatched the moving vehicle out of the air. The force of Prime's strength hurling it sent Superman a few feet back as he attempted to steady it with his own strength, then he quickly brought the car back to the streets, his gaze momentarily scanning those within to make sure that they were all intact. Aside from the terrified looks on their faces? They seemed fine. Hoping that Kara had managed to take hold of the other car, Superman launched himself into the skies again and fell short a few feet away from Prime.
"You need to stop," he told him, expression neutral. "These people haven't done anything to you and neither have we."