Orange didn't die because they had their hands on Cyan's knife, preventing him from stabbing them. I unfortunately couldnt find a clean version of the music that plays behind the kill noise and I really wanted it, so I had to settle with this sound clip even though there is the stabbing noise. But Cyan is not really stabbing Orange. Maybe instead Cyan just gave them cuts on the body or something huahua. At least this is my intention and reasoning.