Even worse, they're called "Quake sounds" even though Quake has no announcer, and Quake isn't the origin of Unreal's memes like MONSTER KILL! Blind misinformation mania, along with those IP myths made up by the kids as an excuse to copy and paste with no inspiration. No, it is NOT okay to use and exploit stolen property (leaked beta assets) to create your new game.
If I were you, i'd immediately hit DEL on that project and start over not piggybacking on other IP.