Lol, yea, the scripts are beyond sketchy. This is the new vector, a cool idea masking itself as "fun" (which it is actually fun). People not understanding or vibing may not understand what they're installing. Even if this author isn't malicious, you cannot assume that will always be the case.
I don't think using something fun as an attack vector is anything new at all. It's an easy way to have someone let their guard down because you want to play around and aren't thinking how something silly could actually be out to get you.
The author might not be malicious, but from going through some of the audio packs, they're really not quality-checking PRs. For instance, sc_medic/sounds/WhereDoesItHurt.mp3 sounds like two-and-a-half sounds stuck together ("Critical? You Rang? Please state the nat--", it cuts off right there, and doesn't include the phrase "Where does it hurt?").
I wouldn't use this repo outside of some kind of sandbox.