Gorgonopsids were carnivores. Inostrancevia, the largest type of gorgonopsian, would've hunted Scutosaurus. Gorgonopsids might have hunted in packs, and would've definitely used its saber-teeth to kill its prey. The mighty gorgonops may have been an ambush predator, despite its size. Gorgonopsids would hide behind rocks or bushes, and wait until their prey was near. Then they would chase them until the victim tired, before inflicting wounds and waiting for the prey to die from blood loss. Of course, we know what happens next. The victorious beast would feast upon the fresh carcass.
A sculpture of an Inostrancevia getting a nice feast.
A Scutosaurus, prey of Inostrancevia and other large Siberian gorgonopsids. Though they don't look at all like them, Scutosaurus was a distant relative to turtles.