Why does cato run right past katniss and peeta?

Cato runs right past Katniss and Peeta because he is focused on the immediate threat posed by the Mutts that have been unleashed in the arena. In that moment, his priority is survival and confronting the Mutts, rather than engaging with Katniss and Peeta, who are not his main concern. This highlights the chaos of the situation and the instinctual drive to evade danger.